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Returns a substring of +self+, or +nil+ if the substring cannot be constructed.
With integer arguments +offset+ and +length+ given,
returns the substring beginning at the given +offset+
and of the given +length+ (as available):
s = '0123456789' # => "0123456789"
s.byteslice(2) # => "2"
s.byteslice(200) # => nil
s.byteslice(4, 3) # => "456"
s.byteslice(4, 30) # => "456789"
Returns +nil+ if +length+ is negative or +offset+ falls outside of +self+:
s.byteslice(4, -1) # => nil
s.byteslice(40, 2) # => nil
Counts backwards from the end of +self+
if +offset+ is negative:
s = '0123456789' # => "0123456789"
s.byteslice(-4) # => "6"
s.byteslice(-4, 3) # => "678"
With Range argument +range+ given, returns
<tt>byteslice(range.begin, range.size)</tt>:
s = '0123456789' # => "0123456789"
s.byteslice(4..6) # => "456"
s.byteslice(-6..-4) # => "456"
s.byteslice(5..2) # => "" # range.size is zero.
s.byteslice(40..42) # => nil
The starting and ending offsets need not be on character boundaries:
s = 'こんにちは'
s.byteslice(0, 3) # => "こ"
s.byteslice(1, 3) # => "\x81\x93\xE3"
The encodings of +self+ and the returned substring
are always the same:
s.encoding # => #<Encoding:UTF-8>
s.byteslice(0, 3).encoding # => #<Encoding:UTF-8>
s.byteslice(1, 3).encoding # => #<Encoding:UTF-8>
But, depending on the character boundaries,
the encoding of the returned substring may not be valid:
s.valid_encoding? # => true
s.byteslice(0, 3).valid_encoding? # => true
s.byteslice(1, 3).valid_encoding? # => false
Related: see {Converting to New String}[rdoc-ref:String@Converting+to+New+String].
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