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This tutorial will demonstrate how to find the maximum value in a list in Python.

This tutorial will cover a number of scenarios and data types, from simple lists of integers to more complex structures like arrays within arrays.

forFinding the Maximum Value in a List Using Loops in Python

A Python forloop can find the maximum value in a list by comparing each value in the array and storing the largest value in a variable.

For example, let's declare an array of random integers and print the maximum value. Also, declare a variable max_valueto store the maximum value and print it after the loop is finished.

numbers = [55, 4, 92, 1, 104, 64, 73, 99, 20]

max_value = None

for num in numbers:
    if max_value is None or num > max_value:
        max_value = num

print("Maximum value:", max_value)

Output:

Maximum value: 104

If you need to further manipulate the output using the index of the maximum value, just use the Python function enumerate, which allows forthe loop to accept a second argument representing the index of the current loop iteration.

Add a new variable max_idxto store the maximum index of the maximum value.

numbers = [55, 4, 92, 1, 104, 64, 73, 99, 20]

max_value = None
max_idx = None

for idx, num in enumerate(numbers):
    if max_value is None or num > max_value:
        max_value = num
        max_idx = idx

print("Maximum value:", max_value, "At index: ", max_idx)

Output:

Maximum value: 104 At index: 4

max()Find the maximum value in a list using the function in Python

Python has a predefined function called max(), which returns the maximum value in a list.

Using max()to find the maximum value only requires one line of code.

numbers = [55, 4, 92, 1, 104, 64, 73, 99, 20]

max_value = max(numbers)
print("Maximum value:", max_value)

Output:

Maximum value: 104

If you need the index of the maximum value, we can call the built-in function in Python lists index(). This function will return the index of the specified element in the array.

numbers = [55, 4, 92, 1, 104, 64, 73, 99, 20]

max_value = max(numbers)
print("Maximum value:", max_value, "At index:", arr.index(max_value))

Output:

Maximum value: 104 At index: 4

max()Finding the maximum value in a list of strings and dictionaries using

The function max()also provides support for string list and dictionary data types.

Given a list of strings, the function max()will return the largest element, sorted alphabetically. The letter Z is the largest value, and A is the smallest value.

strings = ["Elephant", "Kiwi", "Gorilla", "Jaguar", "Kangaroo", "Cat"]

max_value = max(strings)
print("Maximum value:", max_value, "At index:", strings.index(max_value))

Output:

Maximum value: Kiwi At index: 1

Finding the maximum value in a nested list in Python

A more complex example is finding the maximum value of a nested list in Python.

First, we declare the random values ​​in a nested list.

nst = [[1001, 0.0009], [1005, 0.07682], [1201, 0.57894], [1677, 0.0977]]

From this nested list, we want to get the maximum value of the second element in the nested list. We also want to print out the first element and use it as an index. The way nested lists are handled is more like a key-value pair in a list.

To find the maximum value of this complex structure, we can use the function max()and its optional argument key, which remembers the element in the nested list to compare.

nst = [[1001, 0.0009], [1005, 0.07682], [1201, 0.57894], [1677, 0.0977]]

idx, max_value = max(nst, key=lambda item: item[1])

print("Maximum value:", max_value, "At index:", idx)

keyThe parameter accepts a lambda function which will allow the function max()to return a key-value pair.

Output:

Maximum value: 0.57894 At index: 1201

In summary, this tutorial has covered different ways to find the maximum value in different types of lists in Python. Apart max()from , there are also some built-in functions like min(), , all()and any(), which can operate on iterable objects in Python.