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6dbece090f
(https://github.com/ruby/stringio/pull/201) https://github.com/ruby/stringio/commit/26d8f60053
100 lines
3.0 KiB
Plaintext
100 lines
3.0 KiB
Plaintext
Reads and returns a line from the stream;
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returns +nil+ if at end-of-stream.
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Side effects:
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- Increments stream position by the number of bytes read.
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- Assigns the return value to global variable <tt>$_</tt>.
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With no arguments given, reads a line using the default record separator
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(global variable <tt>$/</tt>,* whose initial value is <tt>"\n"</tt>):
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strio = StringIO.new(TEXT)
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strio.pos # => 0
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strio.gets # => "First line\n"
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strio.pos # => 11
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$_ # => "First line\n"
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strio.gets # => "Second line\n"
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strio.read # => "\nFourth line\nFifth line\n"
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strio.eof? # => true
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strio.gets # => nil
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strio = StringIO.new('こんにちは') # Five 3-byte characters.
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strio.pos # => 0
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strio.gets # => "こんにちは"
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strio.pos # => 15
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<b>Argument +sep+</b>
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With only string argument +sep+ given, reads a line using that string as the record separator:
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strio = StringIO.new(TEXT)
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strio.gets(' ') # => "First "
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strio.gets(' ') # => "line\nSecond "
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strio.gets(' ') # => "line\n\nFourth "
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<b>Argument +limit+</b>
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With only integer argument +limit+ given,
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reads a line using the default record separator;
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limits the size (in characters) of each line to the given limit:
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strio = StringIO.new(TEXT)
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strio.gets(10) # => "First line"
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strio.gets(10) # => "\n"
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strio.gets(10) # => "Second lin"
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strio.gets(10) # => "e\n"
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<b>Arguments +sep+ and +limit+</b>
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With arguments +sep+ and +limit+ both given, honors both:
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strio = StringIO.new(TEXT)
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strio.gets(' ', 10) # => "First "
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strio.gets(' ', 10) # => "line\nSecon"
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strio.gets(' ', 10) # => "d "
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<b>Position</b>
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As stated above, method +gets+ reads and returns the next line in the stream.
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In the examples above each +strio+ object starts with its position at beginning-of-stream;
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but in other cases the position may be anywhere:
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strio = StringIO.new(TEXT)
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strio.pos = 12
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strio.gets # => "econd line\n"
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The position need not be at a character boundary:
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strio = StringIO.new('こんにちは') # Five 3-byte characters.
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strio.pos = 3 # At beginning of second character.
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strio.gets # => "んにちは"
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strio.pos = 4 # Within second character.
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strio.gets # => "\x82\x93にちは"
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<b>Special Record Separators</b>
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Like some methods in class IO, method +gets+ honors two special record separators;
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see {Special Line Separators}[https://docs.ruby-lang.org/en/master/IO.html#class-IO-label-Special+Line+Separator+Values]:
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strio = StringIO.new(TEXT)
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strio.gets('') # Read "paragraph" (up to empty line).
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# => "First line\nSecond line\n\n"
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strio = StringIO.new(TEXT)
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strio.gets(nil) # "Slurp": read all.
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# => "First line\nSecond line\n\nFourth line\nFifth line\n"
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<b>Keyword Argument +chomp+</b>
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With keyword argument +chomp+ given as +true+ (the default is +false+),
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removes the trailing newline (if any) from the returned line:
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strio = StringIO.new(TEXT)
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strio.gets # => "First line\n"
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strio.gets(chomp: true) # => "Second line"
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Related: #each_line, #readlines,
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{Kernel#puts}[rdoc-ref:Kernel#puts].
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