December 8, 2007

Search and replace using reg exp

The other day Nathan Strutz wrote a great post on finding and replacing text in your IDE (in my case I’m using Aptana/cfeclipse) using regular expressions.

This is more a reminder to me so that I try to use it (with the idea that it’ll become 2nd nature!), but I also had a play to see how I could use it in day to day coding. I’m sure others have more interesting uses, but here is where I can use it immediately:

Setting variables (using cfml rather than cfscript)

Often you have the need to set a large number of variables, I would actually use a block for this, but if I wanted to use with the end result being something like:

<cfset count = 0 />
<cfset i = 1 />
<cfset j = 1 />

I’ll need a reg exp, text to replace my matched content and initial code to search.

The reg exp

^(.+) (.+)$

Note that I’m using 2 ‘groups’ separated by a space, this will be important when looking at the actual text to search on.

The ‘replace’ text to use

<cfset $1 = $2 />

The initial source code which I’ll search on

count 0
i 1
j i

Note that as have 2 ‘groups’ separated by a space, the end result would be

<cfset count = 0 />
<cfset i = 1 />
<cfset j = 1 />

Nice :) You can use (I believe) as many ‘groups’ as you want, here is an example which uses 3 for <cfparam>

The reg exp

^(.+) (.+) (.+)$

The ‘replace’ text to use

<cfparam name="$1" default=$2 type="$3" />

The initial source code

form.firstName "" string
form.lastName "" string "" email
form.postalcode "90210" numeric

The end result

<cfparam name="form.firstName" default="" type="string" />
<cfparam name="form.lastName" default="" type="string" />
<cfparam name="" default="" type="email" />
<cfparam name="form.postalcode" default="90210" type="numeric" />

As I said, I’m sure there are much better ways to achieve this as I suck at regular expressions. Anyone have any more uses?

© Michael Sharman 2017