Documentation for routine lines

Documentation for routine lines, assembled from the following types:

class Cool

From Cool

(Cool) routine lines

Defined as:

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 Cool, e.g.:

for 'huge-csv'.IO.lines -> $line {
    # Do something with $line 
# or if you'll be processing later 
my @lines = '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 $*IN.lines -> $_ is copy { s/(\w+)/{$0 ~ $0}/.say }

class Str

From Str

(Str) routine lines

multi sub    lines(Str:D $input$limit = Inf --> Positional)
multi method lines(Str:D $input: $limit = 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␤» 

class IO::Handle

From IO::Handle

(IO::Handle) method lines

method lines($limit = Inf)

Return a lazy list of the file's lines read via get, limited to $limit lines. The new line separator (i.e., $* will be excluded.

my @data;
my $data-file = open 'readings.csv';
for $data-file.lines -> $line {

class IO::ArgFiles

From IO::ArgFiles

(IO::ArgFiles) method lines

Return a (lazy) list of the remaining lines in the file pointed to by the file handle.

class IO::Socket::INET

From IO::Socket::INET

(IO::Socket::INET) method lines

method lines()

Returns a lazy list of lines read from the socket.

class Supply

From Supply

(Supply) method lines

method lines(Supply:D: :$chomp = True --> Supply:D)

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.