TypeError: list indices must be integers or slices, not str when I try to iterate lists of strings with special characters inside some of them

colloquial_numbers = ['veinti[\\s|-|]tres', 'veinti[\\s|-|]dos', 'veinti[\\s|-|]uno', 'veinte', 'tres', 'dos', 'uno']

symbolic_numbers = ['23', '22', '21', '20', '3', '2', '1']

body = ''
for n in coloquial_numbers:
    body += """    input_text = re.sub(r"{}", "{}", input_text)\n""".format(coloquial_numbers[n], symbolic_numbers[n])
    #body += """    input_text = re.sub(r'""" + coloquial_numbers[n] + """', '""" + symbolic_numbers[n] + """', input_text)\n"""

print(repr(body))

output:

    input_text = re.sub(r"veinti[\s|-|]*tres", "23", input_text)
    input_text = re.sub(r"veinti[\s|-|]*dos", "22", input_text)
    input_text = re.sub(r"veinti[\s|-|]*uno", "21", input_text)
    input_text = re.sub("tres", "3", input_text)
    input_text = re.sub("dos", "2", input_text)
    input_text = re.sub("uno", "1", input_text)

The error when I iterate this lists:

Traceback (most recent call last):
    body += """    input_text = re.sub(r"{}", "{}", input_text)\n""".format(coloquial_numbers[n], symbolic_numbers[n])
TypeError: list indices must be integers or slices, not str

How could I fix this error? And why does it happen when iterating these lists of strings and with other lists it doesn’t happen?

>Solution :

Here you’re iterating over a list of strings:

colloquial_numbers = ['veinti[\\s|-|]tres', 'veinti[\\s|-|]dos', 'veinti[\\s|-|]uno', 'veinte', 'tres', 'dos', 'uno']
...

for n in colloquial_numbers:
    ...

n is the iterating variable, which means it’s assigned the VALUE of each successive element in the list, not its index. You’re then running colloquial_numbers[n] which, in actual fact, is running
colloquial_numbers['veinti[\\s|-|]tres'], which is incorrect python syntax, since you can’t index a list by using a string

What you can do instead is:

for n in range(len(colloquial_numbers))

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