将 python 列表作为 function 参数传递

Question

I have the below python code

def fir(a,x):
    for i in x:
        h = getx(a,i)
        return h
def getx(a, i):
    print('Hello {} {}'.format(a, i))

print(fir(2,['hi','Helloooooooooooooooo']))

o/P gives me as

Hello 2 hi
None

I dont want None but instead i need

Hello 2 Helloooooooooooooooo

Why is it showing as None?

Answer 1

When you return after a loop, make sure that the 'return' code falls outside of the loop. Otherwise, you'll only return the first iteration. See your code updated below:

def fir(a,x):
    for i in x:
        h = getx(a,i)
    return h
def getx(a, i):
    print('Hello {} {}'.format(a, i))

print(fir(2,['hi','Helloooooooooooooooo']))

Note that the "return h" line is now in line with the for loop, rather than inside it.

Answer 2

You're return -ing at the end of the first loop iteration, so the code only sees "hi".

Answer 3

Take return out of the loop. Collect all the results of getx() in a list and join them in the returned value.

And getx() should return the formatted string rather than printing it, so that the caller can print the result itself.

def fir(a,x):
    return "\n".join(getx(a, i) for i in x)
def getx(a, i):
    return 'Hello {} {}'.format(a, i)

print(fir(2,['hi','Helloooooooooooooooo']))