Re: extracting numbers from a file, excluding words

[Micah Elliott]

On Nov 01, Mike Meyer wrote:
> Kristina Kudriaðova <[EMAIL PROTECTED]> writes:
> 
> > 1 Nov 2005 09:19:45 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]>:
> >> Hi, I have a file with this content:
> >>
> >>  z zzz z
> >> ...
> >> xxx xx x 34.215
> >> zzz zz 
> >> ...
> >>
> >
> > Hi,
> >
> > I'd suggest doing this:
> >
> > f = file('...')
> > for line in f:
> > if 'xxx xx x' in line:
> > var = float(line[len('xxx xx x'):].strip())
> > f.close()
> 
> Alternatively:
> 
> start = len('xxx xx x')
> for line in f:
> if line.startswith('xxx xx x'):
>var = float(line[start:].strip())

To refine this even further, I'll add that 'xxx...' is an ugly pattern
to repeat, and prone to mistyping, so add a tempvar and apply DRY::

pattern = 'xxx xx x'
start = len(pattern)
for line in f:
if line.startswith(pattern):
   var = float(line[start:].strip())

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Re: extracting numbers from a file, excluding words

[Mike Meyer]

Kristina Kudriaðova <[EMAIL PROTECTED]> writes:

> 1 Nov 2005 09:19:45 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]>:
>> Hi, I have a file with this content:
>>
>>  z zzz z
>> ...
>> xxx xx x 34.215
>> zzz zz 
>> ...
>>
>
> Hi,
>
> I'd suggest doing this:
>
> f = file('...')
> for line in f:
> if 'xxx xx x' in line:
> var = float(line[len('xxx xx x'):].strip())
> f.close()

Alternatively:

start = len('xxx xx x')
for line in f:
if line.startswith('xxx xx x'):
   var = float(line[start:].strip())
   
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Re: extracting numbers from a file, excluding words

[Jeffrey Schwab]

Steve Horsley wrote:
> Kristina Kudriašova wrote:
> 
>> 1 Nov 2005 09:19:45 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]>:
>>
>>> Hi, I have a file with this content:
>>>
>>>  z zzz z
>>> ...
>>> xxx xx x 34.215
>>> zzz zz 
>>> ...
>>>
>>
>> Hi,
>>
>> I'd suggest doing this:
>>
>> f = file('...')
>> for line in f:
>> if 'xxx xx x' in line:
>> var = float(line[len('xxx xx x'):].strip())
>> f.close()
> 
> 
> I think I prefer "if line.startswith('xxx xx x'):" . 
> Feels cleaner to me.

Especially if any "z" lines might include the magic pattern.
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Re: extracting numbers from a file, excluding words

[Steve Horsley]

Kristina Kudriašova wrote:
> 1 Nov 2005 09:19:45 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]>:
>> Hi, I have a file with this content:
>>
>>  z zzz z
>> ...
>> xxx xx x 34.215
>> zzz zz 
>> ...
>>
> 
> Hi,
> 
> I'd suggest doing this:
> 
> f = file('...')
> for line in f:
> if 'xxx xx x' in line:
> var = float(line[len('xxx xx x'):].strip())
> f.close()

I think I prefer "if line.startswith('xxx xx 
x'):" . Feels cleaner to me.

Steve
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Re: extracting numbers from a file, excluding words

[Kristina Kudriašova]

1 Nov 2005 09:19:45 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]>:
> Hi, I have a file with this content:
>
>  z zzz z
> ...
> xxx xx x 34.215
> zzz zz 
> ...
>

Hi,

I'd suggest doing this:

f = file('...')
for line in f:
if 'xxx xx x' in line:
var = float(line[len('xxx xx x'):].strip())
f.close()
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extracting numbers from a file, excluding words

[dawenliu]

Hi, I have a file with this content:

 z zzz z
...
xxx xx x 34.215
zzz zz 
...

"x" and "z" are letters.
The lines with "z" are trash, and only the lines with "x" are
important.  I want to extract the number (34.215 in this case) behind
the letters x, and store it in a file.

The sentence "xxx xx x " is FIXED and KNOWN. The "z"
sentences are can vary.  There are also unknown number of "z" lines.

Any suggestions will be appreciated.

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