![Example use with filter()
The filter() function in Python takes in a function and a list as
arguments.
The function is called with all the items in the list and a new list is
returned which contains items for which the function evaluats to
True.
Here is an example use of filter() function to filter out only even
numbers from a list.
# Program to filter out only the even items from a list
my_list = [1, 5, 4, 6, 8, 11, 3, 12]
new_list = list(filter(lambda x: (x%2 == 0) , my_list))
# Output: [4, 6, 8, 12]
print(new_list)](https://image.slidesharecdn.com/lambda-241007170032-7c7b70c7/85/lambda-engineering-students-machine-learnings-pptx-8-320.jpg)
![Example use with map()
The map() function in Python takes in a function and a list.
The function is called with all the items in the list and a new list is
returned which contains items returned by that function for each
item.
Here is an example use of map() function to double all the items in a
list.
# Program to double each item in a list using map()
my_list = [1, 5, 4, 6, 8, 11, 3, 12]
new_list = list(map(lambda x: x * 2 , my_list))
# Output: [2, 10, 8, 12, 16, 22, 6, 24]
print(new_list)](https://image.slidesharecdn.com/lambda-241007170032-7c7b70c7/85/lambda-engineering-students-machine-learnings-pptx-9-320.jpg)
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lambda engineering students machine learnings.pptx
- 1. Artificial Intelligent Python Lambda Function
- 2. Python lambda (Anonymous Functions) In Python, anonymous function means that a function is without a name. As we already know that def keyword is used to define the normal functions and the lambda keyword is used to create anonymous functions. It has the following syntax: lambda arguments: expression • This function can have any number of arguments but only one expression, which is evaluated and returned. • One is free to use lambda functions wherever function objects are required. • You need to keep in your knowledge that lambda functions are syntactically restricted to a single expression. • It has various uses in particular fields of programming besides other types of expressions in functions.
- 3. Python lambda (Anonymous Functions) The following terms may be used interchangeably depending on the programming language type and culture: • Anonymous functions • Lambda functions • Lambda expressions • Lambda abstractions • Lambda form • Function literals
- 4. Example of Lambda Function in python Here is an example of lambda function that doubles the input value. double = lambda x: x * 2# Output: 10 print(double(5)) In the above program, lambda x: x * 2 is the lambda function. Here x is the argument and x * 2 is the expression that gets evaluated and returned. We can now call it as a normal function. double = lambda x: x * 2 is nearly the same as def double(x): return x * 2
- 5. Use of Lambda Function in python The power of lambda is better shown when you use them as an anonymous function inside another function. Say you have a function definition that takes one argument, and that argument will be multiplied with an unknown number: def myfunc(n): return lambda a : a * n Use that function definition to make a function that always doubles the number you send in: Example def myfunc(n): return lambda a : a * n mydoubler = myfunc(2)
- 6. Use of Lambda Function in python Or, use the same function definition to make a function that always triples the number you send in: Example def myfunc(n): return lambda a : a * n mytripler = myfunc(3) print(mytripler(11))
- 7. Use of Lambda Function in python Or, use the same function definition to make both functions, in the same program: Example def myfunc(n): return lambda a : a * n mydoubler = myfunc(2) mytripler = myfunc(3) print(mydoubler(11)) print(mytripler(11)) Use lambda functions when an anonymous function is required for a short period of time.
- 8. Example use with filter() The filter() function in Python takes in a function and a list as arguments. The function is called with all the items in the list and a new list is returned which contains items for which the function evaluats to True. Here is an example use of filter() function to filter out only even numbers from a list. # Program to filter out only the even items from a list my_list = [1, 5, 4, 6, 8, 11, 3, 12] new_list = list(filter(lambda x: (x%2 == 0) , my_list)) # Output: [4, 6, 8, 12] print(new_list)
- 9. Example use with map() The map() function in Python takes in a function and a list. The function is called with all the items in the list and a new list is returned which contains items returned by that function for each item. Here is an example use of map() function to double all the items in a list. # Program to double each item in a list using map() my_list = [1, 5, 4, 6, 8, 11, 3, 12] new_list = list(map(lambda x: x * 2 , my_list)) # Output: [2, 10, 8, 12, 16, 22, 6, 24] print(new_list)