Given a List, perform summation of consecutive elements, by overlapping.

Input: test_list = [4, 7, 3, 2]Output: [11, 10, 5, 6]Explanation: 4 + 7 = 11, 7 + 3 = 10, 3 + 2 = 5, and 2 + 4 = 6.

Input: test_list = [4, 7, 3]Output: [11, 10, 7]Explanation: 4+7=11, 7+3=10, 3+4=7.

**Method 1 : Using list comprehension + zip()**

In this, we zip list, with consecutive elements’ using zip() and then perform summation using + operator. The iteration part is done using list comprehension.

## Python3

`# initializing list` `test_list ` `=` `[` `4` `, ` `7` `, ` `3` `, ` `2` `, ` `9` `, ` `2` `, ` `1` `]` ` ` `# printing original list` `print` `(` `"The original list is : "` `+` `str` `(test_list))` ` ` `# using zip() to get pairing.` `# last element is joined with first for pairing` `res ` `=` `[a ` `+` `b ` `for` `a, b ` `in` `zip` `(test_list, test_list[` `1` `:] ` `+` `[test_list[` `0` `]])]` ` ` `# printing result` `print` `(` `"The Consecutive overlapping Summation : "` `+` `str` `(res))` |

**Output**

The original list is : [4, 7, 3, 2, 9, 2, 1] The Consecutive overlapping Summation : [11, 10, 5, 11, 11, 3, 5]

**Method #2 : Using sum() + list comprehension + zip()**

In this, we perform the task of getting summation using sum() and rest all functionalities kept similar to the above method.

## Python3

`# Python3 code to demonstrate working of ` `# Consecutive overlapping Summation` `# Using sum() + list comprehension + zip()` ` ` `# initializing list` `test_list ` `=` `[` `4` `, ` `7` `, ` `3` `, ` `2` `, ` `9` `, ` `2` `, ` `1` `]` ` ` `# printing original list` `print` `(` `"The original list is : "` `+` `str` `(test_list))` ` ` `# using sum() to compute elements sum` `# last element is joined with first for pairing` `res ` `=` `[` `sum` `(sub) ` `for` `sub ` `in` `zip` `(test_list, test_list[` `1` `:] ` `+` `[test_list[` `0` `]])] ` ` ` `# printing result ` `print` `(` `"The Consecutive overlapping Summation : "` `+` `str` `(res))` |

**Output**

The original list is : [4, 7, 3, 2, 9, 2, 1] The Consecutive overlapping Summation : [11, 10, 5, 11, 11, 3, 5]

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