# Reading ints line from a file in Python

I have to list a integers from a text file separated by newlines into a python list. I ended up with the code above which works (for my case) but certainly is far form optimal.

def readIntegers(pathToFile):

f = open(pathToFile)
f.close()

tmpStr = ""

integers = []

for char in contents:

if char == '\r':
integers.append(int(tmpStr))
tmpStr = ""
continue

if char == '\n':
continue

tmpStr += char

return integers


Now I have much less code, but I'm not sure for which cases split() works correctly.

def readIntegers(pathToFile):

with open(pathToFile) as f:
a = [int(x) for x in f.read().split()]
return a


No need for split (you can use readlines). But no need for readlines, for that matter:

def read_integers(filename):
with open(filename) as f:
return map(int, f)


or, if that’s more to your fancy:

def read_integers(filename):
with open(filename) as f:
return [int(x) for x in f]


A file object is simply iterable in Python, and iterates over its lines.

Note that, contrary to what I said earlier, wrapping the file object in a with block is highly recommended. Python doesn’t actually guarantee (although it recommends it) that objects are disposed of automatically at the end of the scope. Worse, it’s not guaranteed that a file object that is collected actually closes the underlying stream.

(Note that I’ve adapted the method name to Python conventions.)

• Thx for your answer :) I didn't think of using map here. – Nils Jun 11 '12 at 6:02