Using slicing operations, to achieve a trim () function, remove spaces inclusive string, str not call the strip () method

First determines whether the length of the string is 0, if it is, return the string directly

The second cycle is determined whether the string header spaces, and if so, remove spaces, and then determines whether the length of the string is 0, if it is, return the string directly

Third, aft cycle determines whether the string has spaces, and if so, remove spaces, and then determines whether the length of the string is 0, if it is, return the string directly

Finally, return the string

 

Code:

def trim(s):
    if len(s) == 0:
        return s

    while s[0] == ' ':
        s = s[1:]
        if len(s) == 0:
            return s

    while s[-1] == ' ':
        s = s[:-1]
        if len(s) == 0:
            return s

    return s

 

Test code:

IF TRIM ( ' Hello   ' !) = ' Hello ' :
     Print ( ' test failed! ' )
 elif TRIM ( '   Hello ' ) =! ' Hello ' :
     Print ( ' test failed! ' )
 elif TRIM ( '   Hello   ' )! = ' Hello ' :
     Print ( ' ! test failed ' )
 elif TRIM ( '  hello  world  ' !) = ' Hello World ' :
     Print ( ' ! Test failed ' )
 elif TRIM ( ' ' ) =! ' ' :
     Print ( ' ! Test failed ' )
 elif TRIM ( '     ' ) =! ' ' :
     Print ( ' test failed! ' )
 the else :
     Print ( ' test successfully! ' )