切片数组中的字符串对象

Question

def shorten_string(arr):
    newchar = []
    for char in arr:
        #for z in char:
            if char[-2:] == "Ja":
                newchar = char[0:-2]
            elif char[-4:] == "Nein":
                newchar = char[0:-4]
            newchar.append(char)
    return newchar

Reading an array with strings like:

arr = ["KK_abc_Nein","KK_abc_Ja","KK_def_Nein","KK_def_Ja"]

I would like to find out if the last letters match with the string object and then append the String without _Nein or _Ja to the array and return it.

'str' object has no attribute 'append'

most of the time i receive this error.

Answer 1

Basically you are currently overwriting the newchar list by assigning a string to it.

Instead you can use split() , pop() and join() to do the work:

def shorten_string(arr):
known_ends = ["Ja", "Nein"]
newchar = []
for char in arr:
    char = char.split("_")
    end = char.pop()
    if end in known_ends:
        newchar.append("_".join(char))
return newchar

This will work with any number of "words"

>>> arr = ["KK_abc_Nein","KK_abc_Ja","KK_def_Nein","KK_def_Ja"]
>>> shorten_string(arr)
>>> ['KK_abc', 'KK_abc', 'KK_def', 'KK_def']

EDIT: Added list known_ends to easily update the list of ends you want to process instead of overloading the if statement

Answer 2

对于此示例，您可以简单地执行以下操作：

arr = [x.replace('_Nein','').replace('_Ja','') for x in arr]

Answer 3

what about:

arr = ["KK_abc_Nein","KK_abc_Ja","KK_def_Nein","KK_def_Ja"]
b = [ s.replace('_Nein', '').replace('_Ja', '') for s in arr]
print(b)

will output

['KK_abc', 'KK_abc', 'KK_def', 'KK_def']