Answers for "what is the lambda function"

14

lambda function in python

Lamda is just one line anonymous function
Useful when writing function inside function
it can take multiple arguments but computes only one expression

Syntax:
   x = lambda arguments : expression
Posted by: Guest on July-25-2020
3

lambda function in python

In Python, an anonymous function is a function that is defined without a name.

While normal functions are defined using the def keyword in Python, 
anonymous functions are defined using the lambda keyword.

Hence, anonymous functions are also called lambda functions.

# syntax of Lambda function
lambda arguments: expression

# Program to show the use of lambda functions
double = lambda x: x * 2

print(double(5))

# examples
my_list = range(101)

print(list(map(lambda item: item**2, my_list)))
print(list(filter(lambda item: item % 2 == 1, my_list)))
print(list(map(lambda item: item**2, my_list)))

a = [(0, 2), (4, 3), (9, 9), (10, -1)]

a.sort(key=lambda x: x[1])

print(a)

# docs lambda function
# the lambda function can be used as a function inside a function like the following


def make_incrementor(n):
    return lambda x: x + n


f = make_incrementor(12)
print(f(3))
print(f(13))

# you can use lambda as a key for sort or anything else
pairs = [(1, "one"), (2, "two"), (3, "three"), (4, "four")]
# what if you wanna sort the list by the second argument
pairs.sort(key=lambda x: x[1])
print(pairs)
Posted by: Guest on December-31-2020
1

lambda expressions

A lambda expression is a short block 
of code which takes in parameters
and returns a value. Lambda expressions
are similar to methods, but they do
not need a name and they can be
implemented right in the body of a method.

parameter -> expression

To use more than one parameter, wrap them in parentheses:

(parameter1, parameter2) -> expression

Example
Use a lamba expression in the ArrayList's 
forEach() method to print every item in the list:

import java.util.ArrayList;

public class Main {
  public static void main(String[] args) {
    ArrayList<Integer> numbers = new ArrayList<Integer>();
    numbers.add(5);
    numbers.add(9);
    numbers.add(8);
    numbers.add(1);
    numbers.forEach( (n) -> { System.out.println(n); } );
  }
Posted by: Guest on May-31-2021

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