正则表达式：准确输入 4 位数字，检查输入的数字是否出现在前 10,000 个字符中

Question

Anyone can please check my code?

When the user inputs exactly 4 digits, check whether the inputted number appears in the first 10,000 characters (after the decimal) of the text file(which name is "square root of 2.txt") and tell the user its position using.find() method.

Make a new file called inputted_number.txt. Modify the code so that all the valid input is saved in that file. The contents of that file should look something like this:

3210

3222

4771

I don' know how to use re.find(), is that re.search? My codes below:

#import my file 
    myfile = open("sqroot2_10kdigits.txt")
    txt = myfile.read()
    myfile.close()
    
# while True block use re.find
    
    while True:
        try: 
            number = str(input("Enter four digits: "))
            int(number)
            if re.findall(r'\d\d\d\d',txt)) == True:
                print(f'The digits {int(number} appear in the first 10,000 characters of the square root of 2.' )
                print(f'They appear starting on the {starting position}th character after the decimal.' )
      
            else :
                print(f'Sorry, the digits {int(number)} do not appear in the first 10,000 characters of the square root of 2.')
    

#NO.5 make a new file

    with open('inputted_number.txt.', 'w') as filehandle:
        filehandle.write('\n')

Anyone can check my code please!

Answer 1

For what you are describing you do not need a regex.

txt = '2319871325876234897034589734527861' \
    '3098623409862349856243598672354897' \
    '2348776623534078459996505467097201'

while True:
    number = input("Enter four digits (q to quit): ")
    if number.lower() == 'q':
        break
    elif len(number) != 4 or not number.isdigit():
        print("Please enter four numbers")
        continue
    pos = txt.find(number)
    if pos > -1:
        print(
            f'The digits {number} appear in the first '
            '10,000 characters of the square root of 2.'
            f'They appear starting on the {pos}th '
            'character after the decimal.'
        )
    else:
        print(
            f'Sorry, the digits {number} do not appear '
            'in the first 10,000 characters of the '
            'square root of 2.'
        )

Among the changes:

• use str.find not a regex
• no need to cast the string as either a str or an int
• casting as an int will cause trouble with say 0001
• added some basic validation, length and digits