CODEWITHSUNDEEP
python
MacUsers
MacUsers

Reputation: 2229

string manipulation: partly convert to lowercase

As the title says: What's best way of converting a string from any-case to lowercase keeping a portion unchanged? e.g. a string like: FormatDate(%M)==2 or stArTDate(%Y/%m)==11/3 and I want to convert it to formatdate(%M)==2 or startdate(%Y/%m)==11/3 i.e. change it to lowercase except the part in between the braces (). For the first example, I came up something like this:

>>> import re
>>> fdt = re.compile('(F|f)(O|o)(R|r)(M|m)(A|a)(T|t)(D|d)(A|a)(T|t)(E|e)\(')
>>> ss = "forMatDate(%M)==2"
>>> if fdt.match(ss):
...   SS = ss.split('(')
...   SS[0] = SS[0].lower()
...   ss = "(".join(SS)
... 
>>> print ss
formatdate(%M)==2

Whilst it works just fine, I didn't quite like it doing this way. The regular expression is ugly and it makes thing pretty much restricted to a particular string. Is there any better (hence, dynamic) way of doing that? Thanks in advance. Cheers!!

Update:

I probably didn't say it very clearly: it's not always formatdate(), sometimes it's startdate() or enddate() along with UserName==JohnDee and so on.. (it's part of the user-input) but the format is always the same and I wanted something reusable. So, this is the updated version based on Krumelur's script.

>>> fdt = re.compile('\(%[dmwyMW].*\)')
>>> ss = "formatDate(%M)==4"
>>> st = "UserName==JohnDee"
>>>
>>> def dt_lower(sX):
...   if fdt.search(sX):
...     p1,p2 = sX.split('(',1)
...     sX = "%s(%s" % (p1.lower(), p2)
...   else: sX = sX.lower()
...   return sX
... 
>>> print dt_lower(ss)
formatdate(%M)==4
>>>
>>> print dt_lower(st)
username==johndee

This is exactly what I wanted. Thanks everyone for helping. Cheers!!

Upvotes: 3

Views: 310

Answers (5)

Krumelur
Krumelur

Reputation: 32497

Do your strings always look exactly like this? If so, maybe this is enough:

p1,p2 = instr.split('(',1)
lc = '%s(%s' % (p1.lower(), p2)

Upvotes: 5

johnsyweb
johnsyweb

Reputation: 141770

I don't think you can get much more "Pythonic" than this:

Python 2.7.1 (r271:86832, May 27 2011, 21:41:45) 
[GCC 4.2.1 (Apple Inc. build 5664)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> ss = "forMatDate(%M)==2"
>>> if ss.lower().startswith('formatdate'):
...     i,j = ss.split('(', 1)
...     ss = '('.join((i.lower(), j))
... 
>>> ss
'formatdate(%M)==2'

No need for regular expressions, just built-in string methods.

Also works in Python 3.2.

Upvotes: 3

elricL
elricL

Reputation: 1188

Just to add to Krumerlur's answer,u may want to make it

p1,p2 = inst.split( '(' , 1 )

Upvotes: 2

Zach Kelling
Zach Kelling

Reputation: 53819

I don't really get why you are using a regular expression? Why don't you just do:

x, y = ss.split('(')
'('.join((x.lower(), y))

Upvotes: 2

DrTyrsa
DrTyrsa

Reputation: 31941

You can replace your regex check with

if ss.lower().startswith('formatdate'):

Upvotes: 2

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