如何遍历文本文件的行？

Question

I need to take lines from a text file and use them as variables in a python function.

def call(file):
        with open(file) as infile, open('output.txt', 'w') as outfile:
            do stuff in a for loop

file is the variable name and I plan to have a text file containing a list of text file names like so:

hello.txt
world.txt
python.txt

I can call the function with a single file name fine:

call(hello.txt)

But I have a long list of files I need to go through. How can I read the file containing the file names line by line while calling the function once with each file name?

Answer 1

"How can I read the file containing the file names line by line while calling the function once with each file name?" ... you just explained what to do. Supposing your text file containing other filenames is "listoffiles.txt" ,

with open('listoffiles.txt') as fp:
    for line in fp:
        filename = line.strip()
        if filename:
            call(filename)

Note that because call keeps overwriting output.txt you may have other issues.

Depending on other design goals of course, you could have call work on an open file object instead of a file name. This makes the function more generic and potentially useful for other cases such as using other file-like objects such as StringIO .

def call(output, filename):
   with open(filename) as infile:
       # do some stuff directly with file

with open('output.txt', 'w') as output:
    with open('listoffiles.txt') as fp:
        for line in fp:
            filename = line.strip()
            if filename:
                call(output, filename)

Answer 2

in the following example I assign a text file string to an arbitrary variable I then eliminate the '.txt' so as to adhere to variable name convention then I assign the string value of x to a number 2

x='hello.txt' 
x = x.replace(".txt","")  
exec("%s = %d" % (x,2))
print(str(x) + ' is equal to: ' + str(hello))

if you try the code you should get

hello is equal to: 2