how to split a word to make it the same length as another-CodePudding

I have a task to make the words a and b the same length. If they aren't already the same I need to cut of the beginning letters to make them the same and then combine them. The code i have right now works for all the assertions besides "" and "hello" is should return just "" but the code I have right now is returning hello. I have tried making another if statement for this one case but that doesnt work either. If there is something wrong or if i can fix the code i already have to return the correct word.

def removeStart(a, b):

    if len(a) == len(b):
        return a   b

    if len(a) > len(b):
        return a[-len(b):]   b

    if len(a) < len(b):
        return a   b[-len(a):]


# Test Code
assert (removeStart("same", 'lens') == "samelens")
assert (removeStart("Hello", "Hi") == "loHi")
assert (removeStart("", "Hello") == "")

CodePudding user response：

The problem is that if len(a) == 0, then b[-len(a:] will be b[0:] which is just b.

How about the following, using slicing with non-negative indices:

def removeStart(a, b):
    len_common = min(len(a), len(b))
    return a[len(a) - len_common:]   b[len(b) - len_common:]

CodePudding user response：

Your code doesn't work because s[-0:] yield the full string, not an empty string.

Here is as working version:

def removeStart(a, b):
    l = min(len(a), len(b))
    if l == 0:
        return ''
    return a[-l:]   b[-l:]

CodePudding user response：

Add another condition inside removeStart().

def removeStart(a, b):

    if a == "" and b == "Hello":  # this one
        return ""

    if len(a) == len(b):
        return a   b

    if len(a) > len(b):
        return a[-len(b):]   b

    if len(a) < len(b):
        return a   b[-len(a):]


# Test Code
assert (removeStart("same", 'lens') == "samelens")
assert (removeStart("Hello", "Hi") == "loHi")
assert (removeStart("", "Hello") == "")