How to read part of string in Python?

Question

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) ?

print appends a newline at the end by default, if you have a \n in your string, you'll have an empty line after the printed one. — GPhilo
– GPhilo, Commented Aug 6, 2018 at 10:08

GPhilo · Accepted Answer · 2018-08-06 10:49:08Z

1

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)

edited Aug 6, 2018 at 10:49

answered Aug 6, 2018 at 10:14

GPhilo

19.3k9 gold badges70 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

MysteryGuy Over a year ago

I accept this one because it's more intuitive than using regex; thank you @GPhilo, it helps

Rakesh · Accepted Answer · 2018-08-06 10:13:00Z

0

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

answered Aug 6, 2018 at 10:13

Rakesh

82.9k17 gold badges85 silver badges122 bronze badges

Collectives™ on Stack Overflow

How to read part of string in Python?

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related