Parse text file line by line and make tuples every n separator in Python

Question

I have a text file. I want to read the file line by line, split with separator and make tuples every n separator. The example is :

"A-B-C-D 

E-F-G

Thank You!

For Helping

Stranger-seeker "

Output of above lines will look like:

(A,B,C,D)

(E,F,G\n\nThank You!\n\nFor Helping\n\nStranger,seeker)

I will be very grateful if you could help me with the solution in Python.

I have managed to get it with reading whole file at once. I wanted to read line by line instead. — tryCatch, Sep 09 '18 at 04:31

score 0 · Answer 1 · answered Sep 09 '18 at 04:02

0

There is a recipe for grouper in itertools. You can use it to group a list into a fixed length chuncks

>>> from itertools import zip_longest
>>> def grouper(iterable, n, fillvalue=None):
...     "Collect data into fixed-length chunks or blocks"
...     # grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx"
...     args = [iter(iterable)] * n
...     return zip_longest(*args, fillvalue=fillvalue)
... 
>>> data = open('tmp.txt').read().split('-')
>>> list(grouper(data, 4))
[('A', 'B', 'C', 'D\nE'), ('F', 'G\nThank You!\nFor Helping\nStranger', 'seeker\n', None)]

answered Sep 09 '18 at 04:02

Sunitha

11,777
2
20
23

thank you for trying. After 4 fields in the tuple, the new line suggests another record. I am also trying to read the file each line at a time. 'D\nE" is part of second record. – tryCatch Sep 09 '18 at 04:11
`list(grouper(data, 3))` would group the elements in chunks or three. So you would get `[('A', 'B', 'C'), ('D\nE', 'F', 'G\nThank You!\nFor Helping\nStranger'), ('seeker\n', None, None)]` – Sunitha Sep 09 '18 at 04:14

score 0 · Answer 2 · answered Sep 09 '18 at 04:02

You can split the input string and then use list comprehension on a rolling slice of the list:

s = '''A-B-C-D

E-F-G

Thank You!

For Helping

Stranger-seeker'''
l = s.split('-')
print([l[i:i+3] for i in range(0, len(l), 3)])

This outputs:

[['A', 'B', 'C'], ['D\n\nE', 'F', 'G\n\nThank You!\n\nFor Helping\n\nStranger'], ['seeker']]

tryCatch · Answer 3 · 2018-09-09T17:02:42.847

My solution reading the whole file at once is. Please help me improve it.

with open(filename) as fp:

 data = fp.read()
 my_values = data.split('-')
 my_data = []
 count = 0
 rem_values = []
 delimiter_count =  len(my_values) - 1
 for x in range(len(my_values)):
     count += 1
     if count == 4:
         split_val = my_values[x].split("\n")
         if len(split_val) == 2:
             count = 1
             my_data.append(split_val[0] )
             rem_values.append(my_data ) 
             my_data = [ split_val[1] ]
        else:
             count = 1
             my_data.append(split_val[0] )
             rem_values.append(my_data ) 
    else:
        my_data.append( my_values[x] )

print(rem_values)

Parse text file line by line and make tuples every n separator in Python

3 Answers3