Python | Separate odd and even index elements
Python list are quite popular and no matter what type of field one is coding, one has to deal with lists and its various applications. In this particular article, we discuss ways to separate odd and even indexed elements and its reconstruction join. Let’s discuss ways to achieve this.
Method #1 : Using Naive method
Using Naive method, this task can be performed by using the loops. One can use two containers one each to store alternate elements and later joining them.
Python3
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# Python3 code to demonstrate # Separating odd and even index elements # using naive method # initializing list test_list = [3, 6, 7, 8, 9, 2, 1, 5] # printing original list print["The original list : " + str[test_list]] # using naive method # Separating odd and even index elements odd_i = [] even_i = [] for i in range[0, len[test_list]]: if i % 2: even_i.append[test_list[i]] else : odd_i.append[test_list[i]] res = odd_i + even_i # print result print["Separated odd and even index list: " + str[res]] |
Output The original list : [3, 6, 7, 8, 9, 2, 1, 5] Separated odd and even index list: [3, 7, 9, 1, 6, 8, 2, 5]
Method #2 : Using list slicing
This particular task can be easily performed using the list slicing method in a more compact and efficient manner, this is a recommended method to solve this problem.
Python3
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# Python3 code to demonstrate # Separating odd and even index elements # Using list slicing # initializing list test_list = [3, 6, 7, 8, 9, 2, 1, 5] # printing original list print["The original list : " + str[test_list]] # Using list slicing # Separating odd and even index elements res = test_list[::2] + test_list[1::2] # print result print["Separated odd and even index list : " + str[res]] |
Output The original list : [3, 6, 7, 8, 9, 2, 1, 5] Separated odd and even index list : [3, 7, 9, 1, 6, 8, 2, 5]
Article Tags :
Python
Python Programs
Python list-programs
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Program to find only even indexed elements from list in Python
PythonServer Side ProgrammingProgramming
Suppose we have a list of elements called nums. We have to filter out all odd indexed elements, so only return even indexed elements from that list.
So, if the input is like nums = [5,7,6,4,6,9,3,6,2], then the output will be [7, 4, 9, 6]
To solve this, we will follow these steps −
- use python list slicing strategy to solve this problem
- start from index 1, end at the end of list and increase each step by 2, so the slicing
- syntax is [1::2]
Python program to print the elements of an array present on odd position
PythonServer Side ProgrammingProgramming
When it is required to print the elements of a list that is present in odd index/position, a loop can be used to iterate over the elements, and only check the odd positions in the list by specifying the step size as 2 in the range function.
Below is a demonstration of the same −