CODEWITHSUNDEEP
pythonstringsplit
Neeran
Neeran

Reputation: 1793

Formatting line breaks in python strings

I have a string:

f = open("file.txt", r)
message = f.read()

print message
>>> "To: email\ntitle: add title here\nDescription: whatever here\n"

I can split the string by doing:

f_email, f_title, f_description, blank = message.split('\n')

But the problem arises when I have the message like this:

"To: email\ntitle: add title here\nDescription: first line\nSecond line\nthirdline\n"

When I split the string it splits the description as well. I have tried:

f_email, f_title, f_description, blank = message.split('\n',4)

But that obviously returns ValueError because it is splitting more 4 \n's.

Any suggestions?

Upvotes: 1

Views: 4136

Answers (4)

Gergely Sipkai
Gergely Sipkai

Reputation: 166

When you use message.split('\n', 2) you get three parts: first line, second line and remaining lines in one.

Use this form: 

f = open("file.txt")  
f_email, f_title, f_description = f.read.split('\n', 2)  
f.close()

Or this:

f = open("file.txt")  
f_email = f.readline()  
f_title = f.readline()  
f_description = f.read()  
f.close()

Upvotes: 1

Gareth Latty
Gareth Latty

Reputation: 88987

If you don't want to use the text as a whole, and are not under 3.x to use the nice splat unpacking, you can simply do it like this:

email = None
title = None
description = ""
with open("test.txt", "r") as f:
    for number, line in enumerate(f):
       if number == 0:
           email = line.strip()
       elif number == 1:
           title = line.strip()
       else:
           description += line

Upvotes: 1

Rafał Rawicki
Rafał Rawicki

Reputation: 22690

@Hooked gave a good answer for Python2. Since in Python3 * works also for tuple unpacking, you can do:

f_email, f_title, *f_description = tokens

The details are in PEP 3132

Upvotes: 4

Hooked
Hooked

Reputation: 88128

When you run .split('\n') you return a list. Rather than assign the variables when you split, you can pull them out of the list:

tokens = message.split('\n')
f_email = tokens[0]
f_title = tokens[1]
f_description = tokens[2]

This can be made less fragile by checking the size of the list. If you know it needs at least three elements, you can:

assert(len(tokens)>=3)

Another way to get around this is to wrap the thing up in a try/except block:

tokens = message.split('\n')
try:  
    f_description = tokens[2]
except:
    f_description = None

That way you can handle the case for a shorter list the exact way you like!

Upvotes: 4

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