Sorting a list but I keep getting a error-CodePudding

I'm still a python beginner. I need to write 2 lists to two different text files then sort each text file then finally add those two text file outputs to a new text file that is also sorted. I need to sort the ascending order.I tried casting the numbers to str when I did this the program worked to print the unsorted list but the problem came when I added sort .Hope this makes sense.

number1 = [5000, 300, 4, 1, 2]
number2 = [19, 66, 8, 17, 100]

with open("numbers1.txt", "w") as file1:
    file1.write(str(number1))

with open("numbers2.txt", "w") as file2:
    file2.write(str(number2))

with open("numbers1.txt", "r ") as file1:
    content = file1.read()
    content.sort()
    print(content)

with open("numbers2.txt", "r ") as file2:
    content2 = file2.read()
    content2.sort()
    print(content2)
    

#combined =  file1   file2
#combined.sort()
#print(combined)

the program then gives me this error

content.sort()
AttributeError: 'str' object has no attribute 'sort'

I have yet to write the final two sorted lists to a new text file that is also sorted

CodePudding user response：

file.read() returns a string, not a list. You need to convert it back to a list if you want a list, but the format in which you're saving the list to the file in the first place isn't the best, since it creates extra characters.

It's probably a better idea to write one element of the list to each line of the file instead. Then, read the file

with open("numbers1.txt", "w") as file1:
    file1.writelines(str(n) for n in number1)

with open("numbers1.txt", "r ") as file1:
    content = []
    for line in file1:
        content.append(int(line))

    content.sort()

You could replace the read loop with a comprehension:

with open("numbers1.txt", "r ") as file1:
    content = [int(line) for line in file1]
    content.sort()

If it is an option, you could write to a json file instead of a regular text file. The json package takes care of converting the read list to the correct format when you use json.load().

import json

with open("numbers1.json", "w") as file1:
    json.dump(numbers1, file1)

with open("numbers1.txt", "r ") as file1:
    content = json.load(file1)
    content.sort()