Python Loop Won't Iterate On Second Pass

When I run the following in the Python IDLE Shell: f = open(r'H:\Test\test.csv', 'rb') for line in f: print line #this works fine however, when I run the following for a s

Solution 1:

This does not work because you've already seeked to the end of the file the first time. You need to rewind (using .seek(0)) or re-open your file.

Some other pointers:

1. Python has a very good csv module. Do not attempt to implement CSV parsing yourself unless doing so as an educational exercise.
2. You probably want to open your file in 'rU' mode, not 'rb'. 'rU' is universal newline mode, which will deal with source files coming from platforms with different line endings for you.
3. Use with when working with file objects, since it will cleanup the handles for you even in the case of errors. Ex:

.

withopen(r"H:\Test\test.csv", "rU") as f:
    for line in f:
        ...

Solution 2:

Because you've gone all the way through the CSV file, and the iterator is exhausted. You'll need to re-open it before the second loop.