Lucia - 1 year ago 39

Python Question

I wrote a function that tries to find out what has the maximum value in a list:

`def maxElement(L):`

length=len(L)

if L[length-1]>L[length-2]:

del L[length-2]

print L

elif L[length-1]<L[length-2]:

del L[length-1]

return L

print maxElement([1,2,95754754745,3,1,8,444,2,42425])

My output is wrong:

`>>>`

[1, 2, 95754754745L, 3, 1, 8, 444, 42425]

[1, 2, 95754754745L, 3, 1, 8, 444, 42425]

>>>

It doesn't even delete for me what I've ask for. What did I do wrong? I can't get it!

Answer

You are not calling your function again, which makes recursion impossible. Furthermore you have no base case which would stop recursion, which in this case would be:

```
if length == 1:
return L
```

Here is the fixed code:

```
def maxElement(L):
length=len(L)
if length == 1:
return L
elif L[length-1]>=L[length-2]:
del L[length-2]
elif L[length-1]<=L[length-2]:
del L[length-1]
return maxElement(L)
print maxElement([1,2,95754754745,3,1,8,444,2,42425])
```

This outputs:

```
python recursive.py
> [95754754745L]
```

I also added `<=`

and `>=`

on the conditionals to avoid infinite recursion if there are two elements that share the maximum value.

Source (Stackoverflow)