Question on re.IGNORECASE

[chemag]

Hi,

I'm having some problems with basic RE in python. I was wondering
whether
somebody could provide a hint on what's going wrong with the following
script. Comments are included.

TIA.
-myself

python2.3

Python 2.3.4 (#1, Nov 18 2004, 13:39:30)
[GCC 3.2.3 20030502 (Red Hat Linux 3.2.3-39)] on linux2
Type "help", "copyright", "credits" or "license" for more information.# this makes no sense to me. Why is the previous line matched
# and this not?<_sre.SRE_Match object at 0xb758d020>

 

[Kent Johnson]

Hi,

I'm having some problems with basic RE in python. I was wondering
whether
somebody could provide a hint on what's going wrong with the following
script. Comments are included.

TIA.
-myself

python2.3

Python 2.3.4 (#1, Nov 18 2004, 13:39:30)
[GCC 3.2.3 20030502 (Red Hat Linux 3.2.3-39)] on linux2
Type "help", "copyright", "credits" or "license" for more information.

# this makes no sense to me. Why is the previous line matched

Because the second argument to pattern.search() is the position where the search starts, not a flag. re.IGNORECASE == 2 so your search is skipping the first two chars.

Try giving the flags as a second argument to re.compile():<_sre.SRE_Match object at 0x009651B0>

Kent

 

[chemag]

OK, I got it.

- The re module search function syntax is:

search( pattern, string[, flags])

where re.IGNORECASE is a valid flag.

- The RE Object search method syntax is:

search( string[, pos[, endpos]])

where "The optional second parameter pos gives an index in the string
where the search is to start; it defaults to 0"

It turns out that re.IGNORECASE has the value
2.

Am I the only person bitten by this?

http://docs.python.org/lib/node115.html
http://docs.python.org/lib/re-objects.html

-myself

 

[chemag]

Thanks for your help.

-myself