Python: read all text file lines in loop
Just iterate over each line in the file. Python automatically checks for the End of file and closes the file for you (using the with
syntax).
with open('fileName', 'r') as f:
for line in f:
if 'str' in line:
break
There are situations where you can't use the (quite convincing) with... for...
structure. In that case, do the following:
line = self.fo.readline()
if len(line) != 0:
if 'str' in line:
break
This will work because the the readline()
leaves a trailing newline character, where as EOF is just an empty string.
There's no need to check for EOF in python, simply do:
with open('t.ini') as f:
for line in f:
# For Python3, use print(line)
print line
if 'str' in line:
break
Why the with
statement:
It is good practice to use the
with
keyword when dealing with file objects. This has the advantage that the file is properly closed after its suite finishes, even if an exception is raised on the way.