[](*args) public

Element Reference—If passed a single Fixnum, returns a substring of one character at that position. If passed two Fixnum objects, returns a substring starting at the offset given by the first, and a length given by the second. If given a range, a substring containing characters at offsets given by the range is returned. In all three cases, if an offset is negative, it is counted from the end of str. Returns nil if the initial offset falls outside the string, the length is negative, or the beginning of the range is greater than the end of the string.

If a Regexp is supplied, the matching portion of str is returned. If a numeric or name parameter follows the regular expression, that component of the MatchData is returned instead. If a String is given, that string is returned if it occurs in str. In both cases, nil is returned if there is no match.

a = "hello there"
a[1]                   #=> "e"
a[1,3]                 #=> "ell"
a[1..3]                #=> "ell"
a[-3,2]                #=> "er"
a[-4..-2]              #=> "her"
a[12..-1]              #=> nil
a[-2..-4]              #=> ""
a[/[aeiou](.)\1/]      #=> "ell"
a[/[aeiou](.)\1/, 0]   #=> "ell"
a[/[aeiou](.)\1/, 1]   #=> "l"
a[/[aeiou](.)\1/, 2]   #=> nil
a["lo"]                #=> "lo"
a["bye"]               #=> nil
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