The Perl Cheat Sheet - Programming Languages | CS 4700, Study notes of Programming Languages

Download The Perl Cheat Sheet - Programming Languages | CS 4700 and more Study notes Programming Languages in PDF only on Docsity! The Perl Cheat sheet CONTEXTS SIGILS ARRAYS HASHES void $scalar whole: @array %hash scalar @array slice: @array[0, 2] @hash{’a’, ’b’} list %hash element: $array[0] $hash{’a’} &sub *glob SCALAR VALUES number, string, reference, glob, undef REFERENCES \ references $$foo[1] aka $foo->[1] $@%&* dereference $$foo{bar} aka $foo->{bar} [] anon. arrayref ${$$foo[1]}[2] aka $foo->[1]->[2] {} anon. hashref ${$$foo[1]}[2] aka $foo->[1][2] \() list of refs NUMBERS vs STRINGS OPERATOR PRECEDENCE = = -> + . ++ -- == != eq ne ** < > <= >= lt gt le ge ! ~ \ u+ u- <=> cmp =~ !~ * / % x SYNTAX + - . for (LIST) { }, for (a;b;c) { } << >> while ( ) { }, until ( ) { } named uops if ( ) { } elsif ( ) { } else { } < > <= >= lt gt le ge unless ( ) { } elsif ( ) { } else { } == != <=> eq ne cmp for equals foreach (ALWAYS) & | ^ REGEX METACHARS REGEX MODIFIERS && ^ string begin /i case insens. || $ str. end (before \n) /m line based ^$ .. ... + one or more /s . includes \n ?: * zero or more /x ign. wh.space = += -= *= etc. ? zero or one /g global , => {3,7} repeat in range list ops () capture REGEX CHARCLASSES not (?:) no capture . == [^\n] and [] character class \s == [\x20\f\t\r\n] or xor | alternation \w == [A-Za-z0-9_] \b word boundary \d == [0-9] \z string end \S, \W and \D negate SPECIAL VARIABLES $_ default variable $0 program name $/ input separator $\ output separator $| autoflush $! sys/libcall error $@ eval error $$ process ID $. line number @ARGV command line args @INC include paths @_ subroutine args %ENV environment