Python list question

[Fulavik]

How do you find the largest number in a list of integers in Python without using the max() function?

[justADeni]

You can iterate through the list and keep track of the maximum value found so far. Here's a simple way to do it:

def find_largest(numbers):
    if not numbers:
        raise ValueError("The list is empty")
    
    largest = numbers[0]  # Assume the first element is the largest initially
    for num in numbers:
        if num > largest:
            largest = num
    return largest

You can test it like this:

# Example usage:
numbers_list = [3, 5, 7, 2, 8, -1, 4]
largest_number = find_largest(numbers_list)
print("The largest number is:", largest_number)

If that works for you, could you please mark my answer as accepted? Thanks

[LuisJuniorA]

Start from 1 instead of 0 in your for loop (so use for i in range loop instead), to avoid a useless iteration

[justADeni]

If I wasn't okay with O(n+1) I probably wouldn't be using Python anyways, but you are right. There are better solutions below mine anyways, though I somehow don't feel that OP is going to mark anyone's answer as accepted. They got what they wanted.

[LuisJuniorA]

If I wasn't okay with O(n+1) I probably wouldn't be using Python anyways, but you are right.

I mean, yeah, but it's not a valid reason not to optimize code. But yeah, basically the same ngl

though I somehow don't feel that OP is going to mark anyone's answer as accepted. They got what they wanted.

pretty sure he does'nt need the answer anymore, he prob asked chatgpt or google, and now we hope for an accepted answer when he prob doesnt look github anymore

[LazariaInk]

Your next turn is to make a sort of this list!

[LuisJuniorA]

There are actually several ways to achieve your goal.

JustADeni gave an example, but I don't prefer it as it compares the first value twice (leading to one unnecessary iteration).

Here are two possible implementations, but note there are many ways to do this.

def find_largest(list):
    if not list:
        raise ValueError("The list is empty")
    
    max = list[0] 
    for i in range(1, len(list)):
        if list[i] > max:
            max = list[i]
    return max

Or

def find_largest(list):
    if not list:
        raise ValueError("The list is empty")
    
    max = 0
    for i in range(1, len(list)):
        if list[i] > list[max]:
            max = i
    return list[max]

If this works for you, could you please mark my answer as accepted? Thanks!

[LuisJuniorA]

Btw, those can be done with while loops too.
instead of for i in range(1, len(list)): you can do :

max = ...
i = 1
while i < len(list):
...
  i+=1

[CodderPrince]

Can you say how to write two different python code in one single comment and each code have separate copy option?

Can you share your original comment?

[LuisJuniorA]

Not sure what you mean, but

# There are actually several ways to achieve your goal.
### JustADeni gave an example, but I don't prefer it as it compares the first value twice (leading to one unnecessary iteration).

**_Here are two possible implementations, but note there are many ways to do this._**

```python
def find_largest(list):
    if not list:
        raise ValueError("The list is empty")
    
    max = list[0] 
    for i in range(1, len(list)):
        if list[i] > max:
            max = list[i]
    return max
\```

Or

```python
def find_largest(list):
    if not list:
        raise ValueError("The list is empty")
    
    max = 0
    for i in range(1, len(list)):
        if list[i] > list[max]:
            max = i
    return list[max]
\```

### If this works for you, could you please mark my answer as accepted? Thanks!

When you see "\```", remove the \

[CodderPrince]

Thank you!😊

[zephyrzilla]

One with the least number of characters:

def find_largest(nums):
    return min(nums,key=-int)

PS: If this works for you, could you please mark my answer as accepted? Thanks! 😊

[LuisJuniorA]

He said no max function, so we could expect no min function too (as he may want to understand the algorithm behind)

[CodderPrince]

🔹 Finding the Largest Number in a List (Without max())

✅ Iterative Approach

def find_largest(lst):
    if not lst:
        raise ValueError("The list is empty")

    largest = lst[0]
    for num in lst[1:]:
        if num > largest:
            largest = num
    return largest

numbers = [3, 7, 2, 9, 5, 10, 4]
print("Largest number (Iterative):", find_largest(numbers))  # Output: 10

[LuisJuniorA]

O(2n - 1) time complexity as you are iterating through lst (to get every value in your for loop) and also to find the largest number.
Just use len() to get the size of the list instead. Faster, easier, your code is just an unoptimized version of what is already stated.

[VasiKumar]

a=[7,30,2,6,10]


for i in range(1,len(a)):
    for j in range(0,len(a)):
        if a[j] > a[i] :
            b= a[j]
            j+=1
        
print(b)

Well this does the job using two loops.

[LuisJuniorA]

O(n² - 1) when you could do O(n)...

[VasiKumar]

Well he asked for a method I knew this one . But can you give a more improvised one?

[LuisJuniorA]

I gave already, just read other comments

[CodderPrince]

🔹 Finding the Largest Number in a List (Without max())

✅ Iterative Approach

def find_largest(lst):
    if not lst:
        raise ValueError("The list is empty")

    largest = lst[0]
    for num in lst[1:]:
        if num > largest:
            largest = num
    return largest

numbers = [3, 7, 2, 9, 5, 10, 4]
print("Largest number (Iterative):", find_largest(numbers))  # Output: 10

🚀 Reduce Approach

from functools import reduce

def find_largest(lst):
    if not lst:
        raise ValueError("The list is empty")
    return reduce(lambda a, b: a if a > b else b, lst)

print("Largest number (Reduce):", find_largest(numbers))  # Output: 10

🔥 Sorted Approach

def find_largest(lst):
    if not lst:
        raise ValueError("The list is empty")
    return sorted(lst)[-1]

print("Largest number (Sorted):", find_largest(numbers))  # Output: 10

⚡ Heapq Approach

import heapq

def find_largest(lst):
    if not lst:
        raise ValueError("The list is empty")
    return heapq.nlargest(1, lst)[0]

print("Largest number (Heapq):", find_largest(numbers))  # Output: 10

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[LuisJuniorA]

Task: get the maximum

You : LETS SORT THE ARRAY !!!

JUST WHY

Anyways, importing module may be a bad idea as it may increase space complexity.

Also, if he wants to understand the algorithm behind max, the only "valid" one is the iterative one, but your's is REALLY BAD as you use lst[1:]. You iterate through each value twice.

(and you answer seems AI Generated, which is lame, as you are helping someone)

Btw, if you are trying to get the approval of OP, he may not approve anyone as it's been a month.