Combine string recursive-python

Question

I have two string list: A = ['YELLOW'] B = ['BA']

I want to combine these two string using a recursive function to get ['YBAEBALBALBAOBAWBA']

HERE IS my function :

def Combine(A, B):

    if len(A) > 0:
        return str(A[0]) + str(B) + Combine(A[:0], B)

-- I have no idea how recursive works? Could someone please help me!

Nir Alfasi · Accepted Answer · 2017-10-22 01:29:42Z

4

You were very close!

def Combine(A, B):
    if len(A) > 0:
        return str(A[0]) + str(B) + Combine(A[1:], B) # <-- fix 1
    else:
        return '' # <-- fix 2

in order to call recursively with the rest of A you should call A[1:]
you took care of the case that len(A) > 0 but forgot to take care of the case that A ran out of characters (the else)

Running

A = 'YELLOW'
B = 'BA'

print(Combine(A, B))

OUTPUT

YBAEBALBALBAOBAWBA

answered Oct 22, 2017 at 1:29

Nir Alfasi

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