Python strip with \n

This is my problem.

I'm trying to read a text file and then convert the lines into floats. The text file has \n and \t in it though I don't know how to get rid of it.

I tried using line.strip() but it didn't take it off and I got an error when I wanted to convert the stuff to floats. I then tried line.strip("\n") but that didn't work either. My program works fine when I take out the \t and \n from the text file, but it's part of the assignment to get it to work with them.

I really don't know why this isn't working. Thanks for any help.

You should be able to use line.strip('\n') and line.strip('\t'). But these don't modify the line variable...they just return the string with the \n and \t stripped. So you'll have to do something like

line = line.strip('\n')
line = line.strip('\t')

That should work for removing from the start and end. If you have \n and \t in the middle of the string, you need to do

line = line.replace('\n','')
line = line.replace('\t','')

to replace the \n and \t with nothingness.

The strip() method removes whitespace by default, so there is no need to call it with parameters like '\t' or '\n'. However, strings in Python are immutable and can't be modified, i.e. the line.strip() call will not change the line object. The result is a new string which is returned by the call.

As already mentioned, it would help if you posted an example from your input file. If there are more than one number on each line, strip() is not the function to use. Instead you should use split(), which is also a string method.

To conclude, assuming that each line contains several floats separated by whitespace, and that you want to build a list of all the numbers, you can try the following:

floats = []
with open(filename) as f:
    for line in f:
        floats.extend([float(number) for number in line.split()])

You can use:

mylist = []
# Assuming that you have loaded data into a lines variable. 
for line in lines:
    mylist.append(line.strip().split('\t')

to get a python list with only the field values for all the lines of data.

How about using a python regex pattern?

import re
f = open('test.txt', 'r')
strings = re.findall(r"\S+", f.read())

And for your case of line.strip() will not work because Python removes only the leading and trailing characters

> From Python Docs - Return a copy of the string with leading and trailing characters removed. If chars is omitted or None, whitespace characters are removed. If given and not None, chars must be a string; the characters in the string will be stripped from the both ends of the string this method is called on.

pythons csv library is good for this.

http://docs.python.org/library/csv.html

CSV = comma seperated values, but if you set the delimiter = \t, then it works for tab separated values too.

Often, depending on the way you read the lines, in order to get rid of \n from myline, you can take myline[:-1] since \n is the last character of myline.

For the '\t' you can use replace() or strip()

If you're trying to convert lines of floats separated by tab characters, then just float(line) will try to convert the whole line into one float, which will fail if there's more than one. Using strip to get rid of leading and trailing whitespace isn't going to help that fundamental problem.

Maybe you need to split each line into pieces and do something with each piece?