TypeError: can only concatenate list (not "str") to list create a script that concatenates values

I am trying to create a script that concatenates values in files into columns. But unfortunately I get an error: "TypeError: can only concatenate list (not" str ") to list"

What am I doing wrong?

import re  inputList = []  for file in ['text1.txt','text2.txt']:      with open(file,'r') as infile:          k = 0          for line in infile:              i = 0              if i < len(inputList) and k:                  inputList[i].extend(re.sub('[^A-Za-z0-9,]+', '', line).split(","))              else :                  inputList.append(re.sub('[^A-Za-z0-9,]+', '', line).split(","))              i += 1          k = 1  print(inputList)  with open('text3','w') as outfile:      for line in inputList:          outfile.write(line + '\n')  

https://stackoverflow.com/questions/65839209/typeerror-can-only-concatenate-list-not-str-to-list-create-a-script-that-co January 22, 2021 at 12:13PM