Documentation for routine lines
Documentation for routine lines, assembled from the following types:
sub lines(Str(Cool))method lines()
Coerces the invocant (and in sub form, the argument) to Str, decomposes it into lines (with the newline characters stripped), and returns the list of lines.
say lines("a\nb\n").join('|'); # OUTPUT: «a|b␤»say "some\nmore\nlines".lines.elems; # OUTPUT: «3␤»
This method can be used as part of an
IO::Path to process a file line-by-line, since
IO::Path objects inherit from
for 'huge-csv'.IO.lines -># or if you'll be processing latermy = 'huge-csv'.IO.lines;
Without any arguments, sub
lines operates on
$*ARGFILES, which defaults to
$*IN in the absence of any filenames.
To modify values in place use
is copy to force a writable container.
for .lines -> is copy
multi sub lines(Str , = Inf --> Positional)multi method lines(Str : = Inf --> Positional)
Returns a list of lines (without trailing newline characters), i.e. the same as a call to
$input.comb( / ^^ \N* /, $limit ) would.
say lines("a\nb").perl; # OUTPUT: «("a", "b").Seq␤»say lines("a\nb").elems; # OUTPUT: «2␤»say "a\nb".lines.elems; # OUTPUT: «2␤»say "a\n".lines.elems; # OUTPUT: «1␤»
sub lines(IO::Handle = , = Inf, : --> Seq)method lines(IO::Handle: = Inf, : --> Seq)
Return a Seq each element of which is a line from the handle (that is chunks delineated by
.nl-in). If the handle's
.chomp attribute is set to
True, then characters specified by
.nl-in will be stripped from each line.
Reads up to
$limit lines, where
$limit can be a non-negative Int,
Inf, or Whatever (which is interpreted to mean
:$close is set to
True, will close the handle when the file ends or
$limit is reached. Subroutine form defaults to
$*ARGFILES, if no handle is provided.
Attempting to call this method when the handle is in binary mode will result in
X::IO::BinaryMode exception being thrown.
say "The file contains ",'50GB-file'.IO.open.lines.grep(*.contains: 'Perl').elems," lines that mention Perl";# OUTPUT: «The file contains 72 lines that mention Perl␤»
method lines(IO::CatHandle: = Inf, : --> Seq)
IO::Handle.lines. Note that a boundary between source handles is considered to be a newline break.
(my = 'foo'.IO).spurt: "foo\nbar";(my = 'bar'.IO).spurt: 'meow';IO::CatHandle.new(, ).lines.perl.say;# OUTPUT: «("foo", "bar", "meow").Seq␤»
method lines(IO::Path: : = True, : = 'utf8', : = ["\x0A", "\r\n"], |c --> Seq)
Opens the invocant and returns its lines.
The behaviour is equivalent to opening the file specified by the invocant, forwarding the
:$nl-in arguments to
IO::Handle.open, then calling
IO::Handle.lines on that handle, forwarding any of the remaining arguments to that method, and returning the resultant Seq.
NOTE: the lines are ready lazily and the handle used under the hood won't get closed until the returned Seq is fully reified, so ensure it is, or you'll be leaking open file handles. (TIP: use the
say "The file contains ",'50GB-file'.IO.lines.grep(*.contains: 'Perl').elems," lines that mention Perl";# OUTPUT: «The file contains 72 lines that mention Perl␤»
Returns a lazy list of lines read from the socket.
method lines(Supply: : = True --> Supply)
Creates a supply that will emit the characters coming in line by line from a supply that's usually created by some asynchronous I/O operation. The optional :chomp parameter indicates whether to remove line separators: the default is True.