625 lines
20 KiB
Ruby
625 lines
20 KiB
Ruby
# frozen_string_literal: true
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require "forwardable"
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class CSV
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#
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# A CSV::Row is part Array and part Hash. It retains an order for the fields
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# and allows duplicates just as an Array would, but also allows you to access
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# fields by name just as you could if they were in a Hash.
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#
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# All rows returned by CSV will be constructed from this class, if header row
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# processing is activated.
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#
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class Row
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#
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# Constructs a new CSV::Row from +headers+ and +fields+, which are expected
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# to be Arrays. If one Array is shorter than the other, it will be padded
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# with +nil+ objects.
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#
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# The optional +header_row+ parameter can be set to +true+ to indicate, via
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# CSV::Row.header_row?() and CSV::Row.field_row?(), that this is a header
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# row. Otherwise, the row assumes to be a field row.
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#
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# A CSV::Row object supports the following Array methods through delegation:
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#
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# * empty?()
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# * length()
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# * size()
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#
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def initialize(headers, fields, header_row = false)
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@header_row = header_row
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headers.each { |h| h.freeze if h.is_a? String }
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# handle extra headers or fields
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@row = if headers.size >= fields.size
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headers.zip(fields)
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else
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fields.zip(headers).each(&:reverse!)
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end
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end
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# Internal data format used to compare equality.
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attr_reader :row
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protected :row
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### Array Delegation ###
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extend Forwardable
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def_delegators :@row, :empty?, :length, :size
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def initialize_copy(other)
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super_return_value = super
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@row = @row.collect(&:dup)
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super_return_value
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end
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# :call-seq:
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# row.header_row? -> true or false
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#
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# Returns +true+ if this is a header row, +false+ otherwise.
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def header_row?
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@header_row
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end
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# :call-seq:
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# row.field_row? -> true or false
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#
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# Returns +true+ if this is a field row, +false+ otherwise.
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def field_row?
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not header_row?
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end
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# :call-seq:
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# row.headers
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#
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# Returns the headers for this row:
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# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
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# table = CSV.parse(source, headers: true)
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# row = table.first
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# row.headers # => ["Name", "Value"]
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def headers
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@row.map(&:first)
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end
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# :call-seq:
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# field(index)
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# field(header)
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# field(header, offset)
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#
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# Returns the field value for the given +index+ or +header+.
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#
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# ---
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#
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# Fetch field value by \Integer index:
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# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.field(0) # => "foo"
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# row.field(1) # => "bar"
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#
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# Counts backward from the last column if +index+ is negative:
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# row.field(-1) # => "0"
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# row.field(-2) # => "foo"
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#
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# Returns +nil+ if +index+ is out of range:
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# row.field(2) # => nil
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# row.field(-3) # => nil
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#
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# ---
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#
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# Fetch field value by header (first found):
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.field('Name') # => "Foo"
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#
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# Fetch field value by header, ignoring +offset+ leading fields:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.field('Name', 2) # => "Baz"
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#
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# Returns +nil+ if the header does not exist.
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def field(header_or_index, minimum_index = 0)
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# locate the pair
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finder = (header_or_index.is_a?(Integer) || header_or_index.is_a?(Range)) ? :[] : :assoc
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pair = @row[minimum_index..-1].public_send(finder, header_or_index)
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# return the field if we have a pair
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if pair.nil?
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nil
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else
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header_or_index.is_a?(Range) ? pair.map(&:last) : pair.last
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end
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end
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alias_method :[], :field
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#
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# :call-seq:
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# fetch(header)
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# fetch(header, default)
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# fetch(header) {|row| ... }
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#
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# Returns the field value as specified by +header+.
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#
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# ---
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#
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# With the single argument +header+, returns the field value
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# for that header (first found):
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.fetch('Name') # => "Foo"
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#
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# Raises exception +KeyError+ if the header does not exist.
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#
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# ---
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#
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# With arguments +header+ and +default+ given,
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# returns the field value for the header (first found)
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# if the header exists, otherwise returns +default+:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.fetch('Name', '') # => "Foo"
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# row.fetch(:nosuch, '') # => ""
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#
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# ---
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#
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# With argument +header+ and a block given,
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# returns the field value for the header (first found)
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# if the header exists; otherwise calls the block
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# and returns its return value:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.fetch('Name') {|header| fail 'Cannot happen' } # => "Foo"
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# row.fetch(:nosuch) {|header| "Header '#{header} not found'" } # => "Header 'nosuch not found'"
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def fetch(header, *varargs)
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raise ArgumentError, "Too many arguments" if varargs.length > 1
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pair = @row.assoc(header)
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if pair
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pair.last
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else
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if block_given?
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yield header
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elsif varargs.empty?
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raise KeyError, "key not found: #{header}"
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else
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varargs.first
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end
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end
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end
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# :call-seq:
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# row.has_key?(header)
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#
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# Returns +true+ if there is a field with the given +header+,
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# +false+ otherwise.
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def has_key?(header)
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!!@row.assoc(header)
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end
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alias_method :include?, :has_key?
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alias_method :key?, :has_key?
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alias_method :member?, :has_key?
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alias_method :header?, :has_key?
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#
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# :call-seq:
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# row[index] = value -> value
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# row[header, offset] = value -> value
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# row[header] = value -> value
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#
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# Assigns the field value for the given +index+ or +header+;
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# returns +value+.
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#
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# ---
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#
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# Assign field value by \Integer index:
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# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row[0] = 'Bat'
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# row[1] = 3
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# row # => #<CSV::Row "Name":"Bat" "Value":3>
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#
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# Counts backward from the last column if +index+ is negative:
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# row[-1] = 4
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# row[-2] = 'Bam'
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# row # => #<CSV::Row "Name":"Bam" "Value":4>
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#
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# Extends the row with <tt>nil:nil</tt> if positive +index+ is not in the row:
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# row[4] = 5
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# row # => #<CSV::Row "Name":"bad" "Value":4 nil:nil nil:nil nil:5>
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#
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# Raises IndexError if negative +index+ is too small (too far from zero).
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#
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# ---
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#
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# Assign field value by header (first found):
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row['Name'] = 'Bat'
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# row # => #<CSV::Row "Name":"Bat" "Name":"Bar" "Name":"Baz">
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#
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# Assign field value by header, ignoring +offset+ leading fields:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row['Name', 2] = 4
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# row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":4>
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#
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# Append new field by (new) header:
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# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row['New'] = 6
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# row# => #<CSV::Row "Name":"foo" "Value":"0" "New":6>
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def []=(*args)
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value = args.pop
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if args.first.is_a? Integer
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if @row[args.first].nil? # extending past the end with index
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@row[args.first] = [nil, value]
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@row.map! { |pair| pair.nil? ? [nil, nil] : pair }
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else # normal index assignment
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@row[args.first][1] = value
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end
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else
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index = index(*args)
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if index.nil? # appending a field
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self << [args.first, value]
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else # normal header assignment
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@row[index][1] = value
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end
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end
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end
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#
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# :call-seq:
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# row << [header, value] -> self
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# row << hash -> self
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# row << value -> self
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#
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# Adds a field to +self+; returns +self+:
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#
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# If the argument is a 2-element \Array <tt>[header, value]</tt>,
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# a field is added with the given +header+ and +value+:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row << ['NAME', 'Bat']
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# row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" "NAME":"Bat">
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#
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# If the argument is a \Hash, each <tt>key-value</tt> pair is added
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# as a field with header +key+ and value +value+.
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row << {NAME: 'Bat', name: 'Bam'}
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# row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" NAME:"Bat" name:"Bam">
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#
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# Otherwise, the given +value+ is added as a field with no header.
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row << 'Bag'
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# row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" nil:"Bag">
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def <<(arg)
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if arg.is_a?(Array) and arg.size == 2 # appending a header and name
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@row << arg
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elsif arg.is_a?(Hash) # append header and name pairs
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arg.each { |pair| @row << pair }
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else # append field value
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@row << [nil, arg]
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end
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self # for chaining
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end
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# :call-seq:
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# row.push(*values) ->self
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#
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# Appends each of the given +values+ to +self+ as a field; returns +self+:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.push('Bat', 'Bam')
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# row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" nil:"Bat" nil:"Bam">
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def push(*args)
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args.each { |arg| self << arg }
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self # for chaining
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end
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#
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# :call-seq:
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# delete(index) -> [header, value] or nil
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# delete(header) -> [header, value] or empty_array
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# delete(header, offset) -> [header, value] or empty_array
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#
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# Removes a specified field from +self+; returns the 2-element \Array
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# <tt>[header, value]</tt> if the field exists.
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#
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# If an \Integer argument +index+ is given,
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# removes and returns the field at offset +index+,
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# or returns +nil+ if the field does not exist:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.delete(1) # => ["Name", "Bar"]
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# row.delete(50) # => nil
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#
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# Otherwise, if the single argument +header+ is given,
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# removes and returns the first-found field with the given header,
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# of returns a new empty \Array if the field does not exist:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.delete('Name') # => ["Name", "Foo"]
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# row.delete('NAME') # => []
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#
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# If argument +header+ and \Integer argument +offset+ are given,
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# removes and returns the first-found field with the given header
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# whose +index+ is at least as large as +offset+:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.delete('Name', 1) # => ["Name", "Bar"]
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# row.delete('NAME', 1) # => []
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def delete(header_or_index, minimum_index = 0)
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if header_or_index.is_a? Integer # by index
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@row.delete_at(header_or_index)
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elsif i = index(header_or_index, minimum_index) # by header
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@row.delete_at(i)
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else
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[ ]
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end
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end
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# :call-seq:
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# row.delete_if {|header, value| ... } -> self
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#
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# Removes fields from +self+ as selected by the block; returns +self+.
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#
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# Removes each field for which the block returns a truthy value:
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.delete_if {|header, value| value.start_with?('B') } # => true
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# row # => #<CSV::Row "Name":"Foo">
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# row.delete_if {|header, value| header.start_with?('B') } # => false
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#
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# If no block is given, returns a new Enumerator:
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# row.delete_if # => #<Enumerator: #<CSV::Row "Name":"Foo">:delete_if>
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def delete_if(&block)
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return enum_for(__method__) { size } unless block_given?
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@row.delete_if(&block)
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self # for chaining
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end
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# :call-seq:
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# self.fields(*specifiers)
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#
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# Returns field values per the given +specifiers+, which may be any mixture of:
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# - \Integer index.
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# - \Range of \Integer indexes.
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# - 2-element \Array containing a header and offset.
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# - Header.
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# - \Range of headers.
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#
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# For +specifier+ in one of the first four cases above,
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# returns the result of <tt>self.field(specifier)</tt>; see #field.
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#
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# Although there may be any number of +specifiers+,
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# the examples here will illustrate one at a time.
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#
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# When the specifier is an \Integer +index+,
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# returns <tt>self.field(index)</tt>L
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# source = "Name,Name,Name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.fields(1) # => ["Bar"]
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#
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# When the specifier is a \Range of \Integers +range+,
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# returns <tt>self.field(range)</tt>:
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# row.fields(1..2) # => ["Bar", "Baz"]
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#
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# When the specifier is a 2-element \Array +array+,
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# returns <tt>self.field(array)</tt>L
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# row.fields('Name', 1) # => ["Foo", "Bar"]
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#
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# When the specifier is a header +header+,
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# returns <tt>self.field(header)</tt>L
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# row.fields('Name') # => ["Foo"]
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#
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# When the specifier is a \Range of headers +range+,
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# forms a new \Range +new_range+ from the indexes of
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# <tt>range.start</tt> and <tt>range.end</tt>,
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# and returns <tt>self.field(new_range)</tt>:
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# source = "Name,NAME,name\nFoo,Bar,Baz\n"
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# table = CSV.parse(source, headers: true)
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# row = table[0]
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# row.fields('Name'..'NAME') # => ["Foo", "Bar"]
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#
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# Returns all fields if no argument given:
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# row.fields # => ["Foo", "Bar", "Baz"]
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def fields(*headers_and_or_indices)
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if headers_and_or_indices.empty? # return all fields--no arguments
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@row.map(&:last)
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else # or work like values_at()
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all = []
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headers_and_or_indices.each do |h_or_i|
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if h_or_i.is_a? Range
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index_begin = h_or_i.begin.is_a?(Integer) ? h_or_i.begin :
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index(h_or_i.begin)
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index_end = h_or_i.end.is_a?(Integer) ? h_or_i.end :
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index(h_or_i.end)
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new_range = h_or_i.exclude_end? ? (index_begin...index_end) :
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(index_begin..index_end)
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all.concat(fields.values_at(new_range))
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else
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all << field(*Array(h_or_i))
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end
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end
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return all
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end
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end
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alias_method :values_at, :fields
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#
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# :call-seq:
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# index( header )
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# index( header, offset )
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#
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# This method will return the index of a field with the provided +header+.
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|
# The +offset+ can be used to locate duplicate header names, as described in
|
|
# CSV::Row.field().
|
|
#
|
|
def index(header, minimum_index = 0)
|
|
# find the pair
|
|
index = headers[minimum_index..-1].index(header)
|
|
# return the index at the right offset, if we found one
|
|
index.nil? ? nil : index + minimum_index
|
|
end
|
|
|
|
#
|
|
# Returns +true+ if +data+ matches a field in this row, and +false+
|
|
# otherwise.
|
|
#
|
|
def field?(data)
|
|
fields.include? data
|
|
end
|
|
|
|
include Enumerable
|
|
|
|
#
|
|
# Yields each pair of the row as header and field tuples (much like
|
|
# iterating over a Hash). This method returns the row for chaining.
|
|
#
|
|
# If no block is given, an Enumerator is returned.
|
|
#
|
|
# Support for Enumerable.
|
|
#
|
|
def each(&block)
|
|
return enum_for(__method__) { size } unless block_given?
|
|
|
|
@row.each(&block)
|
|
|
|
self # for chaining
|
|
end
|
|
|
|
alias_method :each_pair, :each
|
|
|
|
#
|
|
# Returns +true+ if this row contains the same headers and fields in the
|
|
# same order as +other+.
|
|
#
|
|
def ==(other)
|
|
return @row == other.row if other.is_a? CSV::Row
|
|
@row == other
|
|
end
|
|
|
|
# :call-seq:
|
|
# row.to_h -> hash
|
|
#
|
|
# Returns the new \Hash formed by adding each header-value pair in +self+
|
|
# as a key-value pair in the \Hash.
|
|
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
|
|
# table = CSV.parse(source, headers: true)
|
|
# row = table[0]
|
|
# row.to_h # => {"Name"=>"foo", "Value"=>"0"}
|
|
#
|
|
# Header order is preserved, but repeated headers are ignored:
|
|
# source = "Name,Name,Name\nFoo,Bar,Baz\n"
|
|
# table = CSV.parse(source, headers: true)
|
|
# row = table[0]
|
|
# row.to_h # => {"Name"=>"Foo"}
|
|
def to_h
|
|
hash = {}
|
|
each do |key, _value|
|
|
hash[key] = self[key] unless hash.key?(key)
|
|
end
|
|
hash
|
|
end
|
|
alias_method :to_hash, :to_h
|
|
|
|
alias_method :to_ary, :to_a
|
|
|
|
# :call-seq:
|
|
# row.to_csv -> csv_string
|
|
#
|
|
# Returns the row as a \CSV String. Headers are not included:
|
|
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
|
|
# table = CSV.parse(source, headers: true)
|
|
# row = table[0]
|
|
# row.to_csv # => "foo,0\n"
|
|
def to_csv(**options)
|
|
fields.to_csv(**options)
|
|
end
|
|
alias_method :to_s, :to_csv
|
|
|
|
# :call-seq:
|
|
# row.dig(index_or_header, *identifiers) -> object
|
|
#
|
|
# Finds and returns the object in nested object that is specified
|
|
# by +index_or_header+ and +specifiers+.
|
|
#
|
|
# The nested objects may be instances of various classes.
|
|
# See {Dig Methods}[https://docs.ruby-lang.org/en/master/doc/dig_methods_rdoc.html].
|
|
#
|
|
# Examples:
|
|
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
|
|
# table = CSV.parse(source, headers: true)
|
|
# row = table[0]
|
|
# row.dig(1) # => "0"
|
|
# row.dig('Value') # => "0"
|
|
# row.dig(5) # => nil
|
|
def dig(index_or_header, *indexes)
|
|
value = field(index_or_header)
|
|
if value.nil?
|
|
nil
|
|
elsif indexes.empty?
|
|
value
|
|
else
|
|
unless value.respond_to?(:dig)
|
|
raise TypeError, "#{value.class} does not have \#dig method"
|
|
end
|
|
value.dig(*indexes)
|
|
end
|
|
end
|
|
|
|
# :call-seq:
|
|
# row.inspect -> string
|
|
#
|
|
# Returns an ASCII-compatible \String showing:
|
|
# - Class \CSV::Row.
|
|
# - Header-value pairs.
|
|
# Example:
|
|
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
|
|
# table = CSV.parse(source, headers: true)
|
|
# row = table[0]
|
|
# row.inspect # => "#<CSV::Row \"Name\":\"foo\" \"Value\":\"0\">"
|
|
def inspect
|
|
str = ["#<", self.class.to_s]
|
|
each do |header, field|
|
|
str << " " << (header.is_a?(Symbol) ? header.to_s : header.inspect) <<
|
|
":" << field.inspect
|
|
end
|
|
str << ">"
|
|
begin
|
|
str.join('')
|
|
rescue # any encoding error
|
|
str.map do |s|
|
|
e = Encoding::Converter.asciicompat_encoding(s.encoding)
|
|
e ? s.encode(e) : s.force_encoding("ASCII-8BIT")
|
|
end.join('')
|
|
end
|
|
end
|
|
end
|
|
end
|