Items tagged regularexpressions in 2003
Filters: Year: 2003 × regularexpressions × Sorted by date
“sexeger”[::-1]
Via Ned Batchelder, an article on Reversing Regular Expressions from Perl.com. Otherwise known as Sexeger, these offer a performance boost over normal regular expressions for certain tasks. The basic idea is pretty simple: searching backwards through a string using a regular expression can be a messy business, but by reversing both the string and the expression, running it, then reversing the result far better performance can be achieved (reversing a string is a relatively inexpensive operation). The example code is in Perl, but I couldn’t resist trying it in Python. The challenge is to find the last number occurring in a string.
[... 384 words]Verbose Regular Expressions
Ned Batchelder describes Verbose Python regular expressions. This is one of the things I’ve known about (as in known that they exist) for ages but have never got around to using. I’ve been working with some pretty heavy regular expressions recently that could really do with the clarity of being defined in verbose format with comments.
[... 96 words]