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From: samb on 16 Mar 2010 03:45
Hi,

I'm trying to do something like :

if m = re.match(r'define\s+(\S+)\s*{$', line):
thing = m.group(1)
elif m = re.match(r'include\s+(\S+)$', line):
thing = m.group(1)
else
thing = ""

But in fact I'm not allowed to affect a variable in "if" statement.
My code should then look like :

if re.match(r'define\s+(\S+)\s*{$', line):
m = re.match(r'define\s+(\S+)\s*{$', line)
thing = m.group(1)
elif re.match(r'include\s+(\S+)$', line):
m = re.match(r'include\s+(\S+)$', line)
thing = m.group(1)
else
thing = ""

Which is not nice because I'm doing twice the same instruction
or like :

m = re.match(r'define\s+(\S+)\s*{$', line)
if m:
thing = m.group(1)
else:
m = re.match(r'include\s+(\S+)$', line)
if m:
thing = m.group(1)
else
thing = ""

Which isn't nice neither because I'm going to have maybe 20 match
tests and I wouldn't like to have 20 indentations.

Anyone a recommendation?

Thanks!
From: Paul Rubin on 16 Mar 2010 03:39
samb <sam.bancal(a)gmail.com> writes:
> or like :
>
> m = re.match(r'define\s+(\S+)\s*{$', line)
> if m:
> thing = m.group(1)
> else:
> m = re.match(r'include\s+(\S+)$', line)
> if m:
> thing = m.group(1)
> else
> thing = ""
>
> Which isn't nice neither because I'm going to have maybe 20 match
> tests and I wouldn't like to have 20 indentations.

for pat in [r'define\s+(\S+)\s*{$', r'include\s+(\S+)$', ...]:
m = re.match(pat, line)
...
From: Chris Rebert on 16 Mar 2010 03:58
On Tue, Mar 16, 2010 at 12:45 AM, samb <sam.bancal(a)gmail.com> wrote:
> Hi,
>
> I'm trying to do something like :
>
> if m = re.match(r'define\s+(\S+)\s*{$', line):
>    thing = m.group(1)
> elif m = re.match(r'include\s+(\S+)$', line):
>    thing = m.group(1)
> else
>    thing = ""
>
> But in fact I'm not allowed to affect a variable in "if" statement.
> My code should then look like :
>
> if re.match(r'define\s+(\S+)\s*{$', line):
>    m = re.match(r'define\s+(\S+)\s*{$', line)
>    thing = m.group(1)
> elif re.match(r'include\s+(\S+)$', line):
>    m = re.match(r'include\s+(\S+)$', line)
>    thing = m.group(1)
> else
>    thing = ""
>
> Which is not nice because I'm doing twice the same instruction
> or like :
>
> m = re.match(r'define\s+(\S+)\s*{$', line)
> if m:
>    thing = m.group(1)
> else:
>    m = re.match(r'include\s+(\S+)$', line)
>    if m:
>        thing = m.group(1)
>    else
>        thing = ""
>
> Which isn't nice neither because I'm going to have maybe 20 match
> tests and I wouldn't like to have 20 indentations.
>
> Anyone a recommendation?

def extract_thing(line):
for regex in (r'define\s+(\S+)\s*{$', r'include\s+(\S+)$'):
m = re.match(regex, line)
if m: return m.group(1)
return ""

Or if the real code is more complicated than your example:

def extract_thing(line):
m = re.match(r'define\s+(\S+)\s*{$', line)
if m: return m.group(1)

m = re.match(r'include\s+(\S+)$', line)
if m: return m.group(1)

#etc...

return ""

Cheers,
Chris
--
http://blog.rebertia.com
From: Gary Herron on 16 Mar 2010 04:10
samb wrote:
> Hi,
>
> I'm trying to do something like :
>
> if m = re.match(r'define\s+(\S+)\s*{$', line):
> thing = m.group(1)
> elif m = re.match(r'include\s+(\S+)$', line):
> thing = m.group(1)
> else
> thing = ""
>
> But in fact I'm not allowed to affect a variable in "if" statement.
> My code should then look like :
>
> if re.match(r'define\s+(\S+)\s*{$', line):
> m = re.match(r'define\s+(\S+)\s*{$', line)
> thing = m.group(1)
> elif re.match(r'include\s+(\S+)$', line):
> m = re.match(r'include\s+(\S+)$', line)
> thing = m.group(1)
> else
> thing = ""
>
> Which is not nice because I'm doing twice the same instruction
> or like :
>
> m = re.match(r'define\s+(\S+)\s*{$', line)
> if m:
> thing = m.group(1)
> else:
> m = re.match(r'include\s+(\S+)$', line)
> if m:
> thing = m.group(1)
> else
> thing = ""
>
> Which isn't nice neither because I'm going to have maybe 20 match
> tests and I wouldn't like to have 20 indentations.
>
> Anyone a recommendation?
>

Yes: Use an array of regular expressions and a loop (untested):

exprs = ["...",
"...",
]

thing = ""
for expr in exps:
m = re.match(expr, line)
if m:
thing = m.group(1)
break

> Thanks!
>

Gary Herron

From: samb on 16 Mar 2010 04:37
Thanks for all those suggestions.
They are good!

1) Let's suppose now that instead of just affecting "thing =
m.group(1)", I need to do a piece of logic depending on which match I
entered...

2) Concerning the suggestion :
m = re.match(r'define\s+(\S+)\s*{$', line)
if m:
thing = m.group(1)

m = re.match(r'include\s+(\S+)$', line)
if m:
thing = m.group(1)

#etc...

It means that I'll do all the checks, even if the first one did match
and I know that the next will not...

Thanks again.
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