[Tutor] question regarding regular expression compile

[Evert Rol]

> I am determining a regular expression that can recognize the any of the following strings:
>  
> MAT file log\20101225 deleted
> MAT file billing\20101225 deleted
> MAT file util\20101225 deleted
> MAT file carrier\20101225 deleted
>  
> I begin by creating a regular expression object so that I can reuse it in multiple operations:
>  
>         test = re.compile(‘MAT file
>  
> for log, billing, util, and carrier I use an arbitrary match:
>  
>         (log|billing|util|carrier)
>  
> for 20101225 I use decimal digit with repetition match:
>  
>         \d{8}
>  
> and finish with:
>  
>         delete’)
>  
> My question is how do I handle the backslash (NOTE: the match must only be a backslash)?

Use a raw string (prepend 'r'):

re.compile(r'MAT file (log|billing|util|carrier)\\\d{8} delete')

You'll notice you need to escape the backslash first, and then use a raw string by prepending an 'r' in front of the string, so the backslash gets interpreted correctly (or rather, not interpreted) by the regular expression.

Cheers,

  Evert