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Find Max And Min In A List Python


Working with lists is very common in Python and even more common is to find max and min in a list Python. We will see 3 different methods for each to find min and max in a python list.

A list in python is a collection of user-stored data in order. In a list, data can be of any type like string, integer, float, boolean, etc.

A list can be created by using square brackets [ ]. Example [1, "a", True]

A list can have mixed data or can have only one data type. To find max and min in a list, we will work on a list of numbers. A list that has only integers or float values both negative and positive can be used to find max and min.

find max and min in a list python

Find Maximum Value In List

To find maximum value in a list we will use 3 different methods.

  1. Using max() function
  2. Finding the maximum value using for loop
  3. Using sort() function

1. Using max() function

The max() function is built-in function in python. It returns the maximum value in a list. It takes a list as an argument and returns the maximum value in the list.

The function accepts the list as an argument. Here is the syntax:

max(list)

Let's see an example to find the maximum value in a list.

num = [4, 6, 1, 3, 9, 2]
# Find the maximum value in the list
print(max(num))

Output

9

Max in a list of string

The max() function can also be used to find the maximum value in a list of strings.

To compare the values among strings, the max() function uses their ASCII values. For example, the ASCII value of a is 97 and the ASCII value of z is 122.

str = ["a", "b", "c", "d", "e"]

print(max(str))

Output

e

In the above example, max of the list is e because the ASCII value of e is 101 which is the highest in the list.

Note: max() function does not work on lists of mixed data types.


2. Finding the maximum value using for loop

You can create your own function to find the maximum value in a list using for loop and if condition.

Algorithm to find the maximum value in a list

  1. Create a variable max and assign it to the first element of the list
  2. Create a for loop to iterate over the list
  3. Check if the current element is greater than max, if yes then assign it to max. Now current element will become the new max.
  4. Keep iterating over the list until the end of the list and return max.

The example below is implemented using the above algorithm.

def max_value(list):
    # set first element as max
    max = list[0]
    for i in list:
        # check if the current element is greater than max
        if i > max:
            max = i
    return max

num = [12, 65, 54, 39, 102, 37, 72, 33, 5, -28, 0, 15]
print(max_value(num))

Output

102

The above example will find the maximum value in the list and print it.


3. Using sort() function

The sort() function is another built-in function in python using which we can find the maximum value in a list. The sort() function sorts the list in ascending order, which means smallest stays at the first position and largest stays at the last position.

The sort() function takes a list as an argument. TO get the maximum value in a list, you can sort the list and picks the last element of the list.

num = [12, 65, 54, 39, 102, 37, 72, 33, 5, -28, 0, 15]

# sort the list
num.sort()

max = num[-1]
print(max)

Output

102

The above example sorts the list and then picks the last element from the sorted list which is the maximum value in the list.


Find Minimum Value In List

Again to find the minimum from a list we can use similar 3 methods but this time just to find the minimum value.

  1. Using min() function
  2. Finding the minimum value using for loop
  3. Using sort() function

1. Using min() function

The min() function in python finds the minimum value from a list and returns it. It can work with both numbers and strings as well but not with mixed data types.

In the following example, the min() function finds the minimum value in a list of numbers and prints the output.

num = [4, 6.4, 1, -3, 0, 2.5]
# Find the minimum value in the list
print(min(num))

Output

-3

Min in a list of string

The min() function can also find the minimum value in a list of strings by comparing their ASCII values.

str = ["d", "A", "&", "@", "b"]

print(min(str))

Output:

&

2. Finding the minimum value using for loop

Creating own function to find minimum value in a list by comparing one value to each other.

Algorithm to find the minimum value in a list

  1. Store the first element of the list in a variable min
  2. Now loop through the list element and compare elements from each other. If the current element is less than min, then assign it to min. Now you have the new min value.
  3. Keep repeating the above steps until the end of the list. At the last min variable will have the actual minimum value of the string.
  4. Return min.

Here is the implementation of the above algorithm.

def min_value(list):
    # set first element as min
    min = list[0]
    for i in list:
        # check if the current element is less than min
        if i < min:
            min = i
    return min

num = [12, 65, 54, 39, 102, 37, 72, 33, 5, -28, 0, 15]
print(min_value(num))

Output

-28

The function will find the minimum value in the list and returns it as output.


3. Using sort() function

We can again use the sort() function here to sort the elements of a list in ascending order and then picks the first element of the list which is the minimum value.

num = [12, 65, 54, 39, 102, 37, 72, 33, 5, -28, 0, 15]

min = num[0]
print(min)

Output

-28

The sort() method sorted the element in ascending order which puts the smallest value in the list at the first position which is -28.


Conclusions

In this short guide, we have covered 3 methods for each to find max and min in a list python. We have also covered the min(), max() and sort() as in-built functions in python and also created a custom function to find minimum and maximum.