Python - 如何返回一个字符串，其中每个数字都替换为相应数量的感叹号（！）

Question

Hi I just started out coding and came across this question on my workbook:

Write a function (called excited_string) that takes a single string, s, as an argument and returns a string in which each digit is replaced by the corresponding number of exclamation marks (.).

What the code should do:

>>> excited_string("123")
'!!!!!!'
>>> excited_string(" 1 2 3 4 5")
' ! !! !!! !!!! !!!!!'
>>> excited_string("Wow1 This2 is1 super111 exci2ting")
'Wow! This!! is! super!!! exci!!ting'
>>> excited_string("Wow1 This2 is1 super111 exciting3")
'Wow! This!! is! super!!! exciting!!!'

My code so far:

def excited_string(s):
    new = ''
    for ch in s:
        if ch.isalpha() is False:
            print(int(ch) * '!')

Thanks for any guidance!

edit: I got:

!
!!
!!!

then I got error for excited_string(" 1 2 3 4 5") due to the ' ' (spaces).

Answer 1

You can use string.join() and a list comprehension

s = "1234"
for ch in s:
    if ch.isalpha() is False:
        print("".join("!" for i in range(int(ch))))

Outputs:

!
!!
!!!
!!!!

Answer 2

Usually, when instructions mention "a function returns", you want to use the return syntax. The return syntax will end a function's execution and "give back" whoever called it the value written after return .

def func1():
    x = 5
    return x

def gimme():
    the_value = func1()
    print(the_value)

gimme()

5

You started off well declaring new being a variable meant to hold the final value. And you were correct with the syntax int(ch) * '!' . Strings support the multiplication operator vs a number

x = 'c' * 5
print(x)

ccccc

Now you just need to figure out how to concatenate each piece of string to the final result, in new , before return -ing it. Don't worry about anything fancy, try simple and straightforward first to exercise problem solving.

Good luck!

Answer 3

This should work:

result = ''.join( ['!'*int(c) if c.isdigit() else c for c in a] )

Testing:

>>> a = 'a2b5c2/'
>>> result = ''.join( ['!'*int(c) if c.isdigit() else c for c in a] )
>>> result
'a!!b!!!!!c!!/'
>>>