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# Python | Generate successive element difference list

• Last Updated : 23 Dec, 2018

While working with python, we usually come by many problems that we need to solve in day-day and in development. Specially in development, small tasks of python are desired to be performed in just one line. We discuss some ways to compute a list consisting of elements that are successive difference in the list.

Method #1 : Using list comprehension
Naive method can be used to perform, but as this article discusses the one liner solutions to this particular problem, we start with the list comprehension as a method to perform this task.

 `# Python3 code to demonstrate ``# to generate successive difference list ``# using list comprehension`` ` `# initializing list ``test_list ``=` `[``1``, ``4``, ``5``, ``3``, ``6``]`` ` ` ` `# printing original list ``print` `(``"The original list is : "` `+` `str``(test_list))`` ` `# using list comprehension``# generate successive difference list``res ``=` `[test_list[i ``+` `1``] ``-` `test_list[i] ``for` `i ``in` `range``(``len``(test_list)``-``1``)]`` ` `# printing result``print` `(``"The computed successive difference list is : "` `+` `str``(res))`

Output :

```The original list is : [1, 4, 5, 3, 6]
The computed successive difference list is : [3, 1, -2, 3]
```

Method #2 : Using `zip()`
`zip()` can also be used to perform the similar task and uses the power of negative indices to` zip()` the index element with its next element and hence compute the difference.

 `# Python3 code to demonstrate ``# to generate successive difference list ``# using zip()`` ` `# initializing list ``test_list ``=` `[``1``, ``4``, ``5``, ``3``, ``6``]`` ` `# printing original list ``print` `(``"The original list is : "` `+` `str``(test_list))`` ` `# using zip()``# generate successive difference list``res ``=` `[j ``-` `i ``for` `i, j ``in` `zip``(test_list[: ``-``1``], test_list[``1` `:])]`` ` `# printing result``print` `(``"The computed successive difference list is : "` `+` `str``(res))`

Output :

```The original list is : [1, 4, 5, 3, 6]
The computed successive difference list is : [3, 1, -2, 3]
```

Method #3 : Using `map() + operator.sub`
`map()` can be coupled with the subtraction operator to perform this particular task. This maps the element with its next element and performs the subtraction operation. Other operators can be passed to perform the desired operations.

 `# Python3 code to demonstrate ``# to generate successive difference list ``# using map() + operator.sub``import` `operator`` ` `# initializing list ``test_list ``=` `[``1``, ``4``, ``5``, ``3``, ``6``]`` ` `# printing original list ``print` `(``"The original list is : "` `+` `str``(test_list))`` ` `# using map() + operator.sub``# generate successive difference list``res ``=` `list``(``map``(operator.sub, test_list[``1``:], test_list[:``-``1``]))`` ` `# printing result``print` `(``"The computed successive difference list is : "` `+` `str``(res))`

Output :

```The original list is : [1, 4, 5, 3, 6]
The computed successive difference list is : [3, 1, -2, 3]
```

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