In this article, we will learn about python program to find largest among three numbers with examples. We will see how to use built-in functions, **if-else** condition to achieve our task.

## Getting Started

The task is to find greatest among three numbers using python program. For example,

If **a = 1.3**, **b = 4.3** and **c = 6.5**, then output should be **c = 6.5**

We can do so in below ways –

- Using simple if-else Condition
- Using nested if-else Condition
- Using max() Function
- Using list and max() Function
- Using max() Function and Unpacking
- Using sorted() Function
- Using for Loop

## Using simple if-else Condition

We can simply use **if-else** condition to write python program to find largest among three numbers as shown below –

def findLargest(num1, num2, num3): if num1 >= num2 and num1 >= num3: return num1 elif num2 >= num1 and num2 >= num3: return num2 else: return num3 # Input three numbers num1 = float(input("Enter 1st number: ")) num2 = float(input("Enter 2nd number: ")) num3 = float(input("Enter 3rd number: ")) result = findLargest(num1, num2, num3) print(f"The largest number among {num1}, {num2}, and {num3} is {result}.")

Here,

- We have defined a method
**findLargest**which we will return greatest among three numbers. - Inside
**findLargest**method, we have used**if-else**condition. At first, we are checking if**num1**is greater than**num2**and**num3**or not. If yes,**num1**is greatest among three numbers. - If no, we are checking if
**num2**is greater than**num1**and**num3**or not. If yes,**num2**is greatest among three numbers. - If no, we can return
**num3**as greatest number.

Output:

Enter 1st number: 23.1 Enter 2nd number: 21.2 Enter 3rd number: 65.8 The largest number among 23.1, 21.2, and 65.8 is 65.8.

## Using nested if-else Condition

We can also use **if-else** condition as ternary operator in python. So, if we want to write above program using ternary operator in python, we can do so as shown below –

# Input three numbers num1 = float(input("Enter 1st number: ")) num2 = float(input("Enter 2nd number: ")) num3 = float(input("Enter 3rd number: ")) result = num1 if num1 >= num2 and num1 >= num3 else (num2 if num2 >= num3 else num3) print(f"The largest number among {num1}, {num2}, and {num3} is {result}.")

Output:

Enter 1st number: 4.8 Enter 2nd number: 5.9 Enter 3rd number: 23.89 The largest number among 4.8, 5.9, and 23.89 is 23.89.

## Using max() Function

We can also use **max()** function to write python program to find greatest among three numbers as shown below –

# Input three numbers num1 = float(input("Enter 1st number: ")) num2 = float(input("Enter 2nd number: ")) num3 = float(input("Enter 3rd number: ")) result = max(num1, num2, num3) print(f"The largest number among {num1}, {num2}, and {num3} is {result}.")

Here,

**max()**function takes three numbers as input and returning the greatest among them.- Finally, result is printed using
**print()**function.

Output:

Enter 2nd number: 6.5 Enter 3rd number: 34.9 The largest number among 1.2, 6.5, and 34.9 is 34.9.

## Using list and max() Function

We can also use **max()** function with python list and find maximum among three numbers as shown below –

# Take input three numbers from user num1 = float(input("Enter 1st number: ")) num2 = float(input("Enter 2nd number: ")) num3 = float(input("Enter 3rd number: ")) numbers = [num1, num2, num3] result = max(numbers) print(f"The largest number among {num1}, {num2}, and {num3} is {result}.")

Here,

- We are passing a list of numbers to
**max()**function. **max()**function will then find largest number present in list and return it.- Finally, result is printed using
**print()**function.

Output:

Enter 1st number: 4.8 Enter 2nd number: 5.9 Enter 3rd number: 23.89 The largest number among 4.8, 5.9, and 23.89 is 23.89.

## Using max() Function and Unpacking

In earlier examples, we passed either list or comma separated numbers to **max()** function as parameter. We can also use unpacking concept in python to pass different parameters in **max()** function and re-write python program to find largest among three numbers as shown below –

# Take input three numbers from user numbers = [float(input("Enter number {}: ".format(i+1))) for i in range(3)] largestNumber = max(*numbers) print(f"The largest number is {largestNumber}.")

Here,

- At first, we are accepting three numbers as input from user and storing it in variable –
**numbers** - After that, passing numbers in
**max()**function. - Then,
**max()**function will find largest among three numbers and return it. Returned value is stored in variable –**largestNumber** - After that, we print the result using
**print()**function.

Output:

Enter number 1: 23.1 Enter number 2: 76.9 Enter number 3: 34.6 The largest number is 76.9.

## Using sorted() Function

We can also use **sorted()** function in python to write python program to find largest among three numbers as shown below –

# Input three numbers num1 = float(input("Enter 1st number: ")) num2 = float(input("Enter 2nd number: ")) num3 = float(input("Enter 3rd number: ")) sortedNumbers = sorted([num1, num2, num3]) result = sortedNumbers[-1] print(f"The largest number among {num1}, {num2}, and {num3} is {result}.")

Here,

**sorted()**function takes three numbers as parameter and returns the sorted numbers in ascending order.- We can get largest numbers using [-1] as it will return last number from list.
- Result is then stored in result variable and printed using
**print()**function.

Output:

Enter 1st number: 2.6 Enter 2nd number: 9898.56 Enter 3rd number: 34.98 The largest number among 2.6, 9898.56, and 34.98 is 9898.56.

## Using for Loop

We can also use for loop to find greatest numbers among three numbers.

# Take input three numbers from user numbers = [float(input("Enter number {}: ".format(i+1))) for i in range(3)] largestNumber = numbers[0] for num in numbers: if num > largestNumber: largestNumber = num print(f"The largest number is {largestNumber}")

Here,

- We are using for loop and iterating list one by one.
- In each iteration, we are checking if that number is greater than already stored greatest value, in
**largestNumber**variable, or not. - If yes, then
**largestNumber**value is replaced with current value. - If no, we move to next iteration.

Output:

Enter number 1: 43.6 Enter number 2: 34.7 Enter number 3: 23.98 The largest number is 43.6

Thus, we have seen many ways to write python program to find largest among three numbers using **if-else**, using **for** loop, using built-in method **sorted()** and **max()**.

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