Question

I’m pretty new to python, but I think I catch on fast.

Anyways, I’m making a program (not for class, but to help me) and have come across a problem.

I’m trying to document a list of things, and by things I mean close to a thousand of them, with some repeating. So my problem is this:

I would not like to add redundant names to the list, instead I would just like to add a 2x or 3x before (or after, whichever is simpler) it, and then write that to a txt document.

I’m fine with reading and writing from text documents, but my only problem is the conditional statement, I don’t know how to write it, nor can I find it online.

for lines in list_of_things:
   if(lines=="XXXX x (name of object here)"):

And then whatever under the if statement. My only problem is that the “XXXX” can be replaced with any string number, but I don’t know how to include a variable within a string, if that makes any sense. Even if it is turned into an int, I still don’t know how to use a variable within a conditional.

The only thing I can think of is making multiple if statements, which would be really long.

Any suggestions? I apologize for the wall of text.

Answer 1

I’d suggest looping over the lines in the input file and inserting a key in a dictionary for each one you find, then incrementing the value at the key by one for each instance of the value you find thereafter, then generating your output file from that dictionary.

catalog = {}
for line in input_file:
    if line in catalog:
        catalog[line] += 1
    else:
        catalog[line] = 1

alternatively

from collections import defaultdict
catalog = defaultdict(int)
for line in input_file:
    catalog[line] += 1

Then just run through that dict and print it out to a file.