Error getting variables from files to int() in Python

Question

I'm trying to get a value from a variable inside some files, here is the code:

path = '/opt/log/...'
word = 'somevariable'

def enumeratepaths(path=path):
    paths = []
    for dirpath, dirnames, files in os.walk(path):
        for file in files:
            fullpath = os.path.join(dirpath, file)
            paths.append(fullpath)
    return paths

def read_files(file):
    try:
        file_open = open(file, 'r')
        search = file_open.read()
        find = search.find(word)
        find_start = find + 7
        find_stop = find + 9
        result = int(search[find_start:find_stop])
        return int(result)
    finally:
        file_open.close()

def main():
    for files in enumeratepaths():
        read_files(files)

if __name__ == "__main__":
    main()

The problem is that some files don't have the variable inside, because some error occurred. IN this case, this script returns an error:

    result = int(search[find_start:find_stop])
ValueError: invalid literal for int(): RE

I want to get these values as int, but I'm stuck.

And another question: If the file does not have that search value, how can it be that it returns things like "RE"?

do you have a sample of the file that is outputting the error? — Duniyadnd
– Duniyadnd, Commented Mar 21, 2011 at 18:39

sth · Accepted Answer · 2011-03-21 18:40:32Z

3

If find can't find the string you are searching for, it will return -1. So you can check the return value of search.find(word) to see if word was actually found.

At the moment you just proceed even if the searched word as not found. find_start will end up as 6, find_end as 8, and probably search[6:8] contains the characters "RE", which leads to the error message you see.

answered Mar 21, 2011 at 18:40

sth

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1 Comment

Simão Over a year ago

Thanks, you're right, i just proceed anyway, and got that RE'

Wolph · Accepted Answer · 2011-03-21 19:53:42Z

2

You could solve it like this:

try:
    int(somestring)
except (ValueError, TypeError):
    pass # not an int... what do you want to do now?

Or if you're always checking a string that should be digit only:

if somestring.isdigit():

edited Mar 21, 2011 at 19:53

answered Mar 21, 2011 at 18:42

Wolph

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2 Comments

S.Lott Over a year ago

Please switch the order. The cleaner solution should be first.

Wolph Over a year ago

@S.Lott: fair enough, I've changed it :)

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