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Python program to find second largest number in a list
• Difficulty Level : Easy
• Last Updated : 05 Oct, 2020

Given a list of numbers, the task is to write a Python program to find the second largest number in given list.
Examples:

```Input: list1 = [10, 20, 4]
Output: 10

Input: list2 = [70, 11, 20, 4, 100]
Output: 70
```

Method 1: Sorting is an easier but less optimal method. Given below is an O(n) algorithm to do the same.

## Python3

 `# Python program to find second largest``# number in a list` `# list of numbers - length of``# list should be at least 2``list1 ``=` `[``10``, ``20``, ``4``, ``45``, ``99``]` `mx``=``max``(list1[``0``],list1[``1``])``secondmax``=``min``(list1[``0``],list1[``1``])``n ``=``len``(list1)``for` `i ``in` `range``(``2``,n):``    ``if` `list1[i]>mx:``        ``secondmax``=``mx``        ``mx``=``list1[i]``    ``elif` `list1[i]>secondmax ``and` `\``        ``mx !``=` `list1[i]:``        ``secondmax``=``list1[i]` `print``(``"Second highest number is : "``,\``      ``str``(secondmax))`
Output
```Second highest number is :  45
```

Method 2: Sort the list in ascending order and print the second last element in the list.

## Python3

 `# Python program to find largest``# number in a list` `# list of numbers``list1 ``=` `[``10``, ``20``, ``4``, ``45``, ``99``]` `# sorting the list``list1.sort()` `# printing the second last element``print``(``"Second largest element is:"``, list1[``-``2``])`
Output

```Second largest element is: 45
```

Method 3: By removing the max element from the list

## Python3

 `# Python program to find second largest``# number in a list` `# list of numbers``list1 ``=` `[``10``, ``20``, ``4``, ``45``, ``99``]` `# new_list is a set of list1``new_list ``=` `set``(list1)` `# removing the largest element from temp list``new_list.remove(``max``(new_list))` `# elements in original list are not changed``# print(list1)` `print``(``max``(new_list))`
Output
```45
```

Method 4: Find max list element on inputs provided by the user

## Python3

 `# Python program to find second largest``# number in a list` `# creating empty list``list1 ``=` `[]` `# asking number of elements to put in list``num ``=` `int``(``input``(``"Enter number of elements in list: "``))` `# iterating till num to append elements in list``for` `i ``in` `range``(``1``, num ``+` `1``):``    ``ele ``=` `int``(``input``(``"Enter elements: "``))``    ``list1.append(ele)` `'''``# sort the list   ``list1.sort()``    ` `# print second maximum element``print("Second largest element is:", list1[-2])` `'''` `# print second maximum element using sorted() method``print``(``"Second largest element is:"``, ``sorted``(list1)[``-``2``])`

Output:

```Enter number of elements in list: 4
Enter elements: 12
Enter elements: 19
Enter elements: 1
Enter elements: 99
Second Largest element is: 19
```

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