从文本文件读取列表时，列表不被识别为列表

Question

I am reading lists from a txt file but when I read them back in and saved to a variable Python recognizes it has a string and not a list. Is there any way around this?

def makereport():
    with open('quizdb','r') as quizdata:
        for line in quizdata:
            print(line)
            print(line[1])

Output:

['maths(easy).txt', 'joh17', 'C', 0.0, 0]
'

As you can see when I print by index position it is printing the character and not the actual position(object) in the list

Answer 1

You cannot read in anything from a file other than strings. You need to use a python library for that, like ast :

>>> ast.literal_eval("['maths(easy).txt', 'joh17', 'C', 0.0, 0]")
['maths(easy).txt', 'joh17', 'C', 0.0, 0]

This will interpret the string as an actual list , where you can access indices:

>>> ast.literal_eval("['maths(easy).txt', 'joh17', 'C', 0.0, 0]")[0]
'maths(easy).txt'

Look into json or pickle for more intuitive ways for storing data. It is generally better to use one of these methods rather than actually storing the raw string representation, as clients can simply call json.loads rather than having to evaluate your text file.