trouble getting function to run, python

Question

For my python class I was instructed to create a function that will read a file and report the number of lines, words, and characters. I can get the code to work, but once I try to convert it to a function, it doesn't work. what's wrong? I also need to return the values in a tuple. I keep getting this error:UnboundLocalError: local variable 'line_cnt' referenced before assignment

def file_elem(filenm):
    f = open(filenm,'r')
    wrd_cnt = 0
    char_cnt = 0
    line_len = 0
    while f is open:
        line_cnt = len(f.readlines( ))
        for line in f:
            f_lines = line.split()
            wrd_cnt += len(f_lines)
            no_spaces = ''.join(line.split())
            char_cnt += len(no_spaces)
    return print(line_cnt, wrd_cnt, char_cnt)

import os
x = os.path.join("C:", "\\temp", "practice4.txt")
file_elem(x)

You are returning the result of the function print. You probably want to drop the print from the return line, and print the result outside the function. — Omri Barel
– Omri Barel, Commented Jun 23, 2013 at 19:14
By the way, does this code really works? while f is open looks very suspicious to me... (you are checking whether f and the global function open are the same object). — Omri Barel
– Omri Barel, Commented Jun 23, 2013 at 19:16
while f is open is now my new favourite bit of English which is syntactically valid Python but doesn't do at all what a beginner would expect.. — DSM
– DSM, Commented Jun 23, 2013 at 19:17
I second! while f is open should be a new PEP recommendation! Seems more natural than with open("file") as f! — Atmaram Shetye
– Atmaram Shetye, Commented Jun 23, 2013 at 19:18
I see, when I change the code to with open("file") as f, it does return the first value correctly, but gives 0 for the last two values — kflaw
– kflaw, Commented Jun 23, 2013 at 19:23

Atmaram Shetye · Accepted Answer · 2013-06-23 19:22:47Z

1

Change while f is open to with open(filenm,'r') as f and remove f = open(filenm,'r'). And move the return (line_cnt, wrd_cnt, char_cnt) inside the with block!

Also, you don't need line_cnt = len(f.readlines( )). You should use a counter and increment it. Otherwise the file would be read before your for line in f!

answered Jun 23, 2013 at 19:22

Atmaram Shetye

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kflaw Over a year ago

def file_elem(filenm): f = open(filenm,'r') line_cnt = 0 wrd_cnt = 0 char_cnt = 0 line_cnt = len(f.readlines( )) with open(filenm) as f: for line in f: f_lines = line.split() wrd_cnt += len(f_lines) no_spaces = ''.join(line.split()) char_cnt += len(no_spaces) return (line_cnt, wrd_cnt, char_cnt) import os x = os.path.join("C:", "\\temp", "practice4.txt") print (file_elem(x))

Dek Dekku · Accepted Answer · 2013-06-23 19:15:19Z

1

Change this:

return print(line_cnt, wrd_cnt, char_cnt)

to

return (line_cnt, wrd_cnt, char_cnt)

and this

file_elem(x)

to:

print file_elem(x)

and it should work the same as before. Your function returns the values. Your main program prints them.

answered Jun 23, 2013 at 19:15

Dek Dekku

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3 Comments

kflaw Over a year ago

UnboundLocalError: local variable 'line_cnt' referenced before assignment

Dek Dekku Over a year ago

As Omri Barel said, your while loop won't really work as you expect it to, so line_cnt is not going to be defined, and that's why you get the error.

Atmaram Shetye Over a year ago

Guess the print was withing the while loop initially!

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