Getting different Regular Expression results

[psbasha]

Hi ,

Could anybody help me in fixing this problem.I am getting different results.

Sample1
 import re 
 strLine =' 1 THRU 20    
 sList = re.findall('\d+ THRU \d+|\d+', strLine)
 print sList

O/P is :
['1 THRU 20'] --Which is correct?

Sample2
import re 
strLine ='  8001  THRU 10828  '
sList = re.findall('\d+ THRU \d+|\d+', strLine)
print sList

O/P is :
['8001', '10828'] --Which is different compare to above one?

The correct Output should be :

['8001 THRU 10828']


Thanks
PSB

[bartonc]

Hi ,

Could anybody help me in fixing this problem.I am getting different results.

Sample1
 import re 
 strLine =' 1 THRU 20    
 sList = re.findall('\d+ THRU \d+|\d+', strLine)
 print sList

O/P is :
['1 THRU 20'] --Which is correct?

Sample2
import re 
strLine ='  8001  THRU 10828  '
sList = re.findall('\d+ THRU \d+|\d+', strLine)
print sList

O/P is :
['8001', '10828'] --Which is different compare to above one?

The correct Output should be :

['8001 THRU 10828']


Thanks
PSB

Sample2
import re 
strLine ='  8001  THRU 10828  '
sList = re.findall('\d+ THRU \d+|\d+', strLine)
print sList

Your Regular Expression doesn't take into account 2 spaces between '8001' and 'THRU'.

[psbasha]

Thanks Barton,

How to fix this problem.

PSB

[bartonc]

Thanks Barton,

How to fix this problem.

PSB

You are welcome.

Regular Expressions are a good tool. Well worth the time to learn.

[bvdet]

Thanks Barton,

How to fix this problem.

PSB

>>> strLine ='  8001  THRU 10828  '
>>> sList = re.findall('\d+.+THRU.+\d+|\d+', strLine)
>>> sList
['8001  THRU 10828']
>>>

[psbasha]

Hi BV ,

Thanks for the reply.

I have some issue when I am using the string in this format.How to fix this issue?.

Sample1
import re 
strLine = '1 = 11001 THRU 11848'
sList = re.findall('\d+ THRU \d+|\d+', strLine)
print sList

O/P is : ['1', '11001 THRU 11848']

Sample

import re 
strLine = '1 = 11001 THRU 11848'
sList = re.findall('\d+.+THRU.+\d+|\d+', strLine)
print sList

O/P is : ['1 = 11001 THRU 11848']

I would like to have my Output to be ['1', '11001 THRU 11848'].

Handling the strLine '14 = 8001 THRU 10828 '

O/P to be ['14', '8001 THRU 10828' ].

-PSB

[bvdet]

Hi BV ,

Thanks for the reply.

I have some issue when I am using the string in this format.How to fix this issue?.

Sample1
import re 
strLine = '1 = 11001 THRU 11848'
sList = re.findall('\d+ THRU \d+|\d+', strLine)
print sList

O/P is : ['1', '11001 THRU 11848']

Sample

import re 
strLine = '1 = 11001 THRU 11848'
sList = re.findall('\d+.+THRU.+\d+|\d+', strLine)
print sList

O/P is : ['1 = 11001 THRU 11848']

I would like to have my Output to be ['1', '11001 THRU 11848'].

Handling the strLine '14 = 8001 THRU 10828 '

O/P to be ['14', '8001 THRU 10828' ].

-PSB

>>> strLine = '1 = 11001 THRU 11848'
>>> re.findall(r'\d+ +THRU +\d+|\d+', strLine)
['1', '11001 THRU 11848']
>>> re.findall(r'\d+\s+THRU\s+\d+|\d+', strLine)
['1', '11001 THRU 11848']
>>>

Notice what happens when I rearrange the expression a bit:

>>> re.findall(r'\d+|\d+\s+THRU\s+\d+', strLine)
['1', '11001', '11848']
>>>

[ghostdog74]

Hi BV ,

Thanks for the reply.

I have some issue when I am using the string in this format.How to fix this issue?.

Sample1
import re 
strLine = '1 = 11001 THRU 11848'
sList = re.findall('\d+ THRU \d+|\d+', strLine)
print sList

O/P is : ['1', '11001 THRU 11848']

Sample

import re 
strLine = '1 = 11001 THRU 11848'
sList = re.findall('\d+.+THRU.+\d+|\d+', strLine)
print sList

O/P is : ['1 = 11001 THRU 11848']

I would like to have my Output to be ['1', '11001 THRU 11848'].

Handling the strLine '14 = 8001 THRU 10828 '

O/P to be ['14', '8001 THRU 10828' ].

-PSB

you could have easily got your results with split()

>>> '14 = 8001 THRU 10828'.split(" = ")
['14', '8001 THRU 10828']
>>>

[psbasha]

HI BV,

Thanks for the reply.

Still I have the problem in reading the string data.In my earlier post "Reading and writing a text file " ,I am reading different SETS file format.When I use this regular expression pattern,the earlier file data is not able to read.

Could you please refer to my posting "Reading and writing a text file " and let me know the exact pattern.

-PSB

[bvdet]

HI BV,

Thanks for the reply.

Still I have the problem in reading the string data.In my earlier post "Reading and writing a text file " ,I am reading different SETS file format.When I use this regular expression pattern,the earlier file data is not able to read.

Could you please refer to my posting "Reading and writing a text file " and let me know the exact pattern.

-PSB

PSB - See my last post in the referenced thread. I posted the code for parsing the data as you had described. The only difference between that data and your problem in this thread is extra spaces around keyword "THRU" - is this correct? If so, all you have to do is modify function getThruData(s) slightly as follows:
Old code:

sList = re.findall('\d+ THRU \d+|\d+', s)

New code:

sList = re.findall('\d+ +THRU +\d+|\d+', s)

The added '+' characters enable a match if one or more spaces occur around "THRU". You really need to study that code to understand how it works.

[psbasha]

Hi BV,

Thanks,it is working fine.

How can we decide this "pattern" style while using regular expression?.

Whether we have to go with "trail and error" or we have to get the different possibilities of formats and then decide the pattern.

-PSB

[bvdet]

Hi BV,

Thanks,it is working fine.

How can we decide this "pattern" style while using regular expression?.

Whether we have to go with "trail and error" or we have to get the different possibilities of formats and then decide the pattern.

-PSB

Ideally the data should be in a strict format designed for easy of parsing. My experience has been to determine the different formats then decide how best to parse.

[ghostdog74]

Hi BV,

Thanks,it is working fine.

How can we decide this "pattern" style while using regular expression?.

Whether we have to go with "trail and error" or we have to get the different possibilities of formats and then decide the pattern.

-PSB

You have to sit down and think through what are the different formats that your input file may turn out and then construct the expression to fit all possible scenarios. Regular expression is a powerful tool, at the same time, may confuse new users. Also, too much of it makes debugging and enhancements to your programs difficult. It takes practice to really understand the mechanics of it too. As the saying goes,

Some people, when confronted with a problem, think “I know, I’ll use regular expressions.” Now they have two problems. —Jamie Zawinski,