ruby--ruby/doc/string/split.rdoc

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Returns an array of substrings of +self+
that are the result of splitting +self+
at each occurrence of the given field separator +field_sep+.
When +field_sep+ is <tt>$;</tt>:
- If <tt>$;</tt> is +nil+ (its default value),
the split occurs just as if +field_sep+ were given as a space character
(see below).
- If <tt>$;</tt> is a string,
the split ocurs just as if +field_sep+ were given as that string
(see below).
When +field_sep+ is <tt>' '</tt> and +limit+ is +nil+,
the split occurs at each sequence of whitespace:
'abc def ghi'.split(' ') => ["abc", "def", "ghi"]
"abc \n\tdef\t\n ghi".split(' ') # => ["abc", "def", "ghi"]
'abc def ghi'.split(' ') => ["abc", "def", "ghi"]
''.split(' ') => []
When +field_sep+ is a string different from <tt>' '</tt>
and +limit+ is +nil+,
the split occurs at each occurrence of +field_sep+;
trailing empty substrings are not returned:
'abracadabra'.split('ab') => ["", "racad", "ra"]
'aaabcdaaa'.split('a') => ["", "", "", "bcd"]
''.split('a') => []
'3.14159'.split('1') => ["3.", "4", "59"]
'!@#$%^$&*($)_+'.split('$') # => ["!@#", "%^", "&*(", ")_+"]
'тест'.split('т') => ["", "ес"]
'こんにちは'.split('に') => ["こん", "ちは"]
When +field_sep+ is a Regexp and +limit+ is +nil+,
the split occurs at each occurrence of a match;
trailing empty substrings are not returned:
'abracadabra'.split(/ab/) # => ["", "racad", "ra"]
'aaabcdaaa'.split(/a/) => ["", "", "", "bcd"]
'aaabcdaaa'.split(//) => ["a", "a", "a", "b", "c", "d", "a", "a", "a"]
'1 + 1 == 2'.split(/\W+/) # => ["1", "1", "2"]
If the \Regexp contains groups, their matches are also included
in the returned array:
'1:2:3'.split(/(:)()()/, 2) # => ["1", ":", "", "", "2:3"]
As seen above, if +limit+ is +nil+,
trailing empty substrings are not returned;
the same is true if +limit+ is zero:
'aaabcdaaa'.split('a') => ["", "", "", "bcd"]
'aaabcdaaa'.split('a', 0) # => ["", "", "", "bcd"]
If +limit+ is positive integer +n+, no more than <tt>n - 1-</tt>
splits occur, so that at most +n+ substrings are returned,
and trailing empty substrings are included:
'aaabcdaaa'.split('a', 1) # => ["aaabcdaaa"]
'aaabcdaaa'.split('a', 2) # => ["", "aabcdaaa"]
'aaabcdaaa'.split('a', 5) # => ["", "", "", "bcd", "aa"]
'aaabcdaaa'.split('a', 7) # => ["", "", "", "bcd", "", "", ""]
'aaabcdaaa'.split('a', 8) # => ["", "", "", "bcd", "", "", ""]
Note that if +field_sep+ is a \Regexp containing groups,
their matches are in the returned array, but do not count toward the limit.
If +limit+ is negative, it behaves the same as if +limit+ was +nil+,
meaning that there is no limit,
and trailing empty substrings are included:
'aaabcdaaa'.split('a', -1) # => ["", "", "", "bcd", "", "", ""]
If a block is given, it is called with each substring:
'abc def ghi'.split(' ') {|substring| p substring }
Output:
"abc"
"def"
"ghi"
Related: String#partition, String#rpartition.