regular expression to replace space by underscore

[a2rodger]

I am using the following code to replace spaces with "_" for my URL rewriting
function.

$url = urlencode(preg_replace("/\s/e" , "_" , $url));


It get thrown the following error and can't figure out what it's trying to tell me,

Notice: Use of undefined constant _ - assumed '_' in : regexp code on line 1

Help!

(Note: I'm using PHP Version 5.2.4)

[code green]

It get thrown the following error and can't figure out what it's trying to tell me

Notice: Use of undefined constant _ - assumed '_' in : regexp code on line 1

When php finds characters outside quotes it knows it is useable code.
A lone word with no dollar $ in front is assumed to be a constant.
Constants should be defined before use or an error is generated
This means you have an underscore outside the quotes somewhere.
[PHP]preg_replace("/\s/e" , "_" , $url));[/PHP]
Use single quotes to avoid confusion but it may be in $url.

[ericoos]

please i want creat a step by step online form, pls kindly give me steps to creat it thanks

[a2rodger]

Getting rid of the 'e' seemed to solve the problem.
Although I'm not sure why.

preg_replace("/\s/" , "_" , $url));

[code green]

The slashes indicate the beginning and end of an expression not the quotes.
So the 'e' was ouside the expression

[Markus]

The slashes indicate the beginning and end of an expression not the quotes.
So the 'e' was ouside the expression

As was intended; the 'e' is a modifier and, therefore, comes after the expression.

[code green]

And the e-modifier treats the replacement string as php code.

[ronverdonk]

A new thread has been split off this one. See want to lear regular expressions

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