How to Fix the 'TypeError: List Indices Must Be Integers or Slices, Not Str' Error in Python?

TypeError: List Indices Must Be Integers

The error "TypeError: list indices must be integers or slices, not str" occurs when you attempt to access a list item using a string index instead of an integer or slice. This error is common when merging two lists into a single array for CSV export.

To avoid this error, follow these steps:

1. Convert the length of the second list (array_dates) to an integer, as indices must always be integers.

   array_length = len(array_dates)

2. Iterate through the new array_length integer using the range function, which automatically increments the iterator value.

   for i in range(array_length):  # Use `xrange` for Python 2.

3. Remove the line i = 1 from your loop, as it's no longer necessary.

You can also streamline your code by using zip to combine the two lists, since they have the same length:

result_array = zip(array_dates, array_urls)
csv_file.writerows(result_array)

Here's the corrected code:

def fill_csv(self, array_urls, array_dates, csv_file_path):
    array_length = len(array_dates)

    # We fill the CSV file
    with open(csv_file_path, "w") as file:
        csv_file = csv.writer(file, delimiter=';', lineterminator='\n')

        # We merge the two arrays in one
        result_array = []
        for i in range(array_length):
            result_array[i][0].append(array_urls[i])
            result_array[i][1].append(array_dates[i])

        csv_file.writerows(result_array)

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