Perl

I'm leaving Perl, traded it for Python. Some shortcuts I'd like to remember

WARNING

Checking existence of a hash element creates the parent keys (autovivification). Always check top-down.

Things that do work

Print out the contents of $variable in a structured format.

use Data::Dumper;
print Dumper($variable);

$var += <value>

Add <value> to $var (works for -, *, / too)

$string .= $addstring

Concatenate $string and $addstring

$string =~ s/<regexp>/<newvalue>/[g]

Substitute <regexp> with <newvalue> in $string. The g modifier makes the all occurrences of <regexp> are substituted.

$newstring = substr($string,start,length)

Return substring of $string

sprintf(format,$string)

Return formatted string. format is e.g. "%.3f". Check Python:Strings#Advanced for all formats.