How to count lines in a text file ?

[Ling Lee]

Thanks for you replies :)

I just ran the program with a different file name, and it only counts the 
number of lines in the file named test.txt. I try to give it a nother try 
with your input...

Thanks again... for the fast reply... Hope I get it right this time :)



"Phil Frost" <indigo at bitglue.com> wrote in message 
news:mailman.3562.1095686871.5135.python-list at python.org...
> Yes, you need a for loop, and a count variable. You can count in several
> ways. File objects are iterable, and they iterate over the lines in the
> file. readlines() returns a list of the lines, which will have the same
> effect, but because it builds the entire list in memory first, it uses
> more memory. Example:
>
> ########
>
> filename = raw_input('file? ')
> file = open(filename)
>
> lines = 0
> for line in file:
>  # line is ignored here, but it contains each line of the file,
>  # including the newline
>  lines += 1
>
> print '%r has %r lines' % (filename, lines)
>
> ########
>
> another alternative is to use the standard posix program "wc" with the
> -l option, but this isn't Python.
>
> On Mon, Sep 20, 2004 at 03:18:53PM +0200, Ling Lee wrote:
>> Hi all.
>>
>> I'm trying to write a program that:
>> 1) Ask me what file I want to count number of lines in, and then counts 
>> the
>> lines and writes the answear out.
>>
>> 2) I made the first part like this:
>>
>> in_file = raw_input("What is the name of the file you want to open: ")
>> in_file = open("test.txt","r")
>> text = in_file.read()
>>
>> 3) I think that I have to use a for loop ( something like: for line in 
>> text:
>> count +=1)
>> Or maybee I have to do create a def: something like: ( def loop(line,
>> count)), but not sure how to do this properly.
>> And then perhaps use the readlines() function, but again not quite sure 
>> how
>> to do this. So do one of you have a good idea.
>>
>> Thanks for all help