检测输入是否同时包含字母和数字的问题

Question

When running this code below with input that includes both letters and numbers it prints not...

# test for both numbers and letters
def multi_test(analysis_input):
    alpha_test = False
    number_test = False
    if analysis_input.isalpha():
     alpha_test = True
     if analysis_input.isnumeric():
        number_test = True
        if alpha_test and number_test:
         print(analysis_input,'is multiple charcters')
        else:
         print('not')



analysis_input = input('enter your string arguement')
multi_test(analysis_input)

Answer 1

You need to check for each character:

def multi_test(analysis_input):
    alpha_test = False
    number_test = False
    for char in analysis_input:
        if char.isalpha():
            alpha_test = True
        if char.isnumeric():
            number_test = True
    if alpha_test and number_test:
        print(analysis_input,'is multiple charcters')
    else:
        print('not')



analysis_input = input('enter your string arguement')
multi_test(analysis_input)

EDIT: a perhaps faster and nicer method is using regex

^(?=.*[a-zA-Z]+)(?=.*\d+).+
# pseudo code, i'm not sure if this code works but its something like this
return bool(re.match(analysis_input, ^(?=.*[a-zA-Z]+)(?=.*\d+).+))

Idea from https://stackoverflow.com/a/24656216/10875953

Answer 2

For fun, here is an alternative strategy. Set up a list of the tests. For each char run all tests until one is a match. When one test is positive, remove it from the list of tests. When the list is empty, you've matched all requirements and can stop.

This method will have the advantage of only running the necessary tests and stopping as soon as you matched all tests once:

def multi_test(s):
    tests = [str.isalpha, str.isdigit]
    for char in s:   # for each character
        for i,test in enumerate(tests):
            if test(char):    # if test is positive
                tests.pop(i)  # remove it from the list of tests
                break
        if len(tests) == 0:  # if there is no test remaining
            return True      # this is a success, we're done
    return False

multi_test('abc1')
# True

Answer 3

You don't need to check every character. Your approach went in the right direction, but the indentation of the if statements and your logic was a bit questionable. After removing all the redundant parts you get

def multi_test(analysis_input):
    if analysis_input.isnumeric() or analysis_input.isalpha():
        print(analysis_input,'is not mixed')
    else:
        print(analysis_input,'is mixed charcters')

Some test cases

for i in ['1234','12ab', 'abcd','1234abcd']:
    multi_test(i)

Output

1234 is not mixed
12ab is mixed charcters
abcd is not mixed
1234abcd is mixed charcters