Given a list containing Positive and Negative integers, We have to find number of times the sign(Positive or Negative) changes in the list.
Input: [-1, 2, 3, -4, 5, -6, 7, 8, -9, 10, -11, 12] Output:9 Explanation : Sign change from -1 to 2, ans = 1 Sign change from 3 to -4, ans = 2 Sign change from -4 to 5, ans = 3 Sign change from 5 to -6, ans = 4 Sign change from -6 to 7, ans = 5 Sign change from 8 to -9, ans = 6 Sign change from -9 to 10, ans = 7 Sign change from 10 to -11 ans = 8 Sign change from -11 to 12, ans = 9 Input: [-1, 2, 3, -4, 5, -11, 12] Output:5 Explanation : Sign change from -1 to 2, ans = 1 Sign change from 3 to -4, ans = 2 Sign change from -4 to 5, ans = 3 Sign change from 5 to -11, ans = 4 Sign change from -11 to 12, ans = 5
Let’s discuss certain ways in which this task is performed.
Method #1: Using Iteration
Using Iteration to find number of time sign changes in the list.
Method #2: Using Itertools and groupby
This is yet another way to perform this particular task using itertools.
Method #3: Using Zip
The most concise and readable way to find number of time sign changes in the list is using zip.
- Python program to count positive and negative numbers in a list
- Python | Rearrange Positive and Negative Elements
- Lambda expression in Python to rearrange positive and negative numbers
- Python | Reverse sign of each element in given list
- Counting the frequencies in a list using dictionary in Python
- Python | Convert list of numerical string to list of Integers
- Python program to print negative numbers in a list
- Python | Get positive elements from given list of lists
- Python program to print positive numbers in a list
- Program to check if a number is Positive, Negative, Odd, Even, Zero
- Python | Converting all strings in list to integers
- Python | Convert number to list of integers
- Python | Summation of integers in heterogenous list
- Python | Adding K to each element in a list of integers
- Python | Program to print duplicates from a list of integers
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.