CODEWITHSUNDEEP
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MysteryGuy
MysteryGuy

Reputation: 1161

How to read part of string in Python?

I have a database containing folders with files. I manage to read the files and get specific lines containing the montage word...

montage = 0, FP1-F7: EEG FP1-REF -- EEG F7-REF
montage = 1, F7-T3: EEG F7-REF -- EEG T3-REF
montage = 2, T3-T5: EEG T3-REF -- EEG T5-REF
montage = 3, T5-O1: EEG T5-REF -- EEG O1-REF

Now, I want to be able to extract what is between the comma and the double point (i.e. FP1-F7, F7-T3,...) but I don't know how to do ?

Moreover, why does the print command display lines with a "space" between (not shown below but real) ?

Upvotes: 1

Views: 87

Answers (2)

GPhilo
GPhilo

Reputation: 19153

Getting the token you want (note: this works with the samples you provided, if there's other commas or colons before the points you show, this won't work):

def parse_line(line):
  start = line.find(',')
  end = line.find(':')
  return line[start+1:end].strip()

You can also do this with regex, but IMO for this scenario that's overkilling.

Getting the list of tokens then can be done with a list comprehension:

tokens = [parse_line(l) for l in lines]

where lines is the list of lines to parse (or, if you're reading from a text file, the file object itself)

Upvotes: 1

Rakesh
Rakesh

Reputation: 82795

Using Regex.

import re
s = """montage = 0, FP1-F7: EEG FP1-REF --  EEG F7-REF
montage = 1, F7-T3:  EEG F7-REF  --  EEG T3-REF
montage = 2, T3-T5:  EEG T3-REF  --  EEG T5-REF
montage = 3, T5-O1:  EEG T5-REF  --  EEG O1-REF """

for i in s.splitlines():
    m = re.search(r",(.*?):", i)     #Get content between , and :
    if m:
        print(m.group(1).strip())

Output:

FP1-F7
F7-T3
T3-T5
T5-O1

Upvotes: 0

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