How to use lambda function in Python

How to use lambda function in Python : The lambda function is used to construct anonymous function and use the lambda keyword. The lambda function will take a number of arguments and have one expression. The tutorial below will give the explanation of the lambda function with its syntax, examples and the uses. The overall explanation will is there in this tutorial.
Lambdas:-
The term lambda is known as an anonymous function and introduced to the field of mathematics by Alonzo church in the 1930s. There are many languages where lambda functions used like c, c++, etc.
The meaning of anonymous means function is with name and known as the def keyword.
This keyword is used to define normal functions and used to create the functions.

Lambdas Function Syntax:-

      lambda argument: expression

The function will have number an of arguments evaluated and returned.
The users are present for a particular field and other types of expression.
Python will aloe not to declare a function in a standard manner using def.
The function is used to define parts as:-

• The parameters
• Function body
• The lambda keyword

The lambda is written in a single line code and invoked immediately.
The lambda keyword is used for calling functions that will accept a function as an argument.
The build-in sorted function accepts and key argument and used to compute keys.
The lambda function assigns to a variable as a part of a bigger function.
Lambda function will lie and return the function of the object.

Use of the lambda function:-

The function us used for the use at the onetime also lambda function known as the throw away function and like filter (), map (), etc.
The function will reduce code lines and compare with the normal function.
IIFE in the python lambda:-
The long form of IIFE is the immediately invoke function execution. It calls and defines also invoke the arguments to the function.
filter() function in lambda:-
This function is used to select sequence of elements and sequence is like list, sets, and tuples.
Use of python as build-in:-
This function will provide a way to perform the operation using the build-in function, because lambda can invoke immediately and pass argument.
The elements will take the parameters as:-

• A sequence of iterators like list, tuple, etc.
• The function and filtering constraints.

Lambda Function Example:-

Sequences=[10,2,8,7,5,4,3,11,0,1]
filtered_result=filter (lambda x: x>4, sequences)
print(list (filtered_result))

Output:-
   [10, 8, 7, 5, 11]

Explanation:-

• From the first statement we define list called as sequence which contain the numbers.
• Declare variable called as the filtered_result and store filtered values returned by filter ().
• The function will run each element of the list and return a true value if it’s greater than 4.
• Then the result is declared.

 

Lambdas in map ():-

This function is used to apply the operation to every element in sequence like filter() and has two parameters,

• The function will define op to perform operation on elements.
• The one or more sequence.

The example is given as follows,
sequences= [10, 2, 8, 7, 4, 3, 11, 0, 1]
filtered_result=map (lambda x: x*x, sequences)
print(list (filtered_result))
Output:-
    [100, 4, 64, 49, 25, 16, 121, 0, 1]
Explanation:-
Defining the list called sequence and contain some numbers.
Also declare the variable called filtered_resullt and store mapped values.
The function will run on each element and return the square of the number.
Then at last print the map function.

Lambda with argument:-

           The lambda function is easy will define with one argument.
Example:-
f=lambda x: x*x
f(5)
Output:-
25
If define lambda function which accepts more and one argument and separate input argument.
The following example will take two integers argument and return,
f=lambda x, y: x*y
f(5, 2)
             10

Why we use lambda function:-

Lambda is treated as a regular function at the interpreter level. The lambda will provide syntax for writing the functions and return the single expression.
The common uses for lambdas are functional programming as support of programming is called functional programming.
The lambda will offer and way to create one-time function passes it as a parameter.
When should we not use lambda function:-
We should not write the function which is complicated and difficult for the coders to build the function. Making the complex one-time expression and superior practice to define and proper function.