I have tried to do this:
A = [["test1"],["test2"]]
A[0][0], A[1][0] = A[1][0], A[0][0]
When executing print(A) the output is as expected: The two entries are swapped.
With this code however "TypeError: "str" object does not support item assignment" (line 8) is being raised:
import sys
try:
with open ("Values", "r") as f:
lines = f.readlines()
for i in range(len(lines)):
for j in range(len(lines[i])//2):
lines[i][j], lines[i][len(lines[i])-1-j] = lines[i][len(lines[i])-1-j], lines[i][j]
except FileNotFoundError:
print("File could not be found.")
You essentially already answered your question. "python strings are not mutable" while lists are.
See you can do
l = ['a','b','c']
l[0] = x
# ['x','b','c']
while you can't do
l = 'abc'
l[0] = x
# TypeError: "str" object does not support item assignment
And your line lines[i][j] tries to change one character in a string.
Instead try converting the string to a list first. Then swapping the characters. Then converting it back to a string:
temp = list(lines[i])
temp[j], temp[len(lines[i])-1-j] = temp[len(lines[i])-1-j], temp[j]
lines[i] = "".join(temp)