CODEWITHSUNDEEP
python
Julie G
Julie G

Reputation: 13

function to find max number in list

I am trying to create a function which finds the max number in a list (without using the max() command)

however my function doesn't work for negative numbers I don't think? how do I fix this? thanks! for example in my second print test it prints 0 instead of -3. 

def my_max(data):
    """finds max number in list"""
    maximum = 0 
    for num in data:
        if num > maximum:
            maximum = num
    return maximum 
print(my_max([11, 99, 3, -6]))
print(my_max([-3, -5, -9, -10]))

Upvotes: 1

Views: 2842

Answers (3)

Nenri
Nenri

Reputation: 528

You have 2 solutions to that:

  • Putting a ridiculously big negative number as initial maximum like -10000000 (won't work in any case and is ugly) or -math.inf (will work in any case but is still ugly)

  • Putting the first item of your list as initial maximum (data[0]) (will work in any case).

    Explanation for this 2nd solution : If the first item of your list is the biggest one, the condition will always resolve to False and this inital maximum will be returned, or, it'll replace it by an other bigger item in the list and finally return the biggest.

Upvotes: 1

Levi Lesches
Levi Lesches

Reputation: 1611

One of the more obscure number types in Python is math.inf -- infinity. This can be produced by:

from math import inf, and then using inf or -inf (negative infinity),

or

float("inf") for positive infinity, and float ("-inf") for negative infinity

Upvotes: 0

Alain T.
Alain T.

Reputation: 42129

This is because you are initializing you maximum variable with an arbitrary value (zero) that is already larger than -3. Try initializing it with the first element in the list maximum = data[0]

Upvotes: 2

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