In this tutorial, we are going to write an anonymous function using lambda to rearrange positive and negative number in a list. We need the pick the negative numbers and then positive numbers from a list to create a new one.
Algorithm
Let's see how to solve the problem step by step.
1. Initialize a list with negative and positive numbers. 2. Write a lambda expression the takes a list as an argument. 2.1. Iterate over the list and get negative numbers 2.2. Same for positive numbers 2.3. Combine both using concatination operator. 3. Return the resultant list.
Note - Use the list comprehension to get negative and positive numbers.
Example
See the code below if you stuck at any point.
# initializing a list arr = [3, 4, -2, -10, 23, 20, -44, 1, -23] # lambda expression rearrange_numbers = lambda arr: [x for x in arr if x < 0] + [x for x in arr if x >= 0] # rearranging the arr new_arr = rearrange_numbers(arr) # printing the resultant array print(new_arr)
Output
If you execute the above program, then you will get the following output.
[-2, -10, -44, -23, 3, 4, 23, 20, 1]
Conclusion
Lambda functions are great for a small operation that need to be perform many times in a program. If you have any doubts regarding the tutorial, mention them in the comment section.