Conditional Statement to compare line of a text file to each line of another file

Question

I'm trying to compare multiple lists in Python. The idea is that we have multiple lists and are comparing each item in each list to a list of aggregated unique values. We then create an excel sheet where we would show each list side by side and any values missing from a particular list would show as PLACEHOLDER in that cell.

(I had a hard time explaining, but if you don't understand after reading please ask questions and I'll adjust the explanation accordingly )

filecount = 0
for file in files:
    filecount += 1
    with open(file) as file_object:
        row = 0
        for line in agg_Names:
            #if line match, output to row
            print (file_object)
            if line in file_object.readlines():
                worksheet.write(row, filecount, line)
                row += 1
                print ("found match")

The last if statement isn't right. It's supposed to compare each item in agg_Names to the current list and output the value. Currently, I'm only getting matches on the first row.

Answer 1

The reason why you're getting only a single line is because readlines() returns all the lines of the file as a list and your comparison happens only once.

So, after your first iteration, file_object.readlines() would be empty because the buffer ( file_object ) is empty.

You can modify your code to this,

filecount = 0
for file in files:
    filecount += 1
    with open(file) as file_object:
        file_lines = file_object.readlines()
    row = 0
    for line in agg_Names:
        #if line match, output to row
        if line in file_lines:
            worksheet.write(row, filecount, line)
            row += 1
            print ("found match")

Hope this helps.