# Most Important Python Functions

Introduction to The Most Important Functions in Python.

Python is one of the best programming languages to learn mainly because of its simple syntax and great versatility. However, due to the large number of built-in functions it provides, it can be difficult to fully assimilate particularly useful functions. In this article, I’ll walk you through the 3 most important Python functions you should learn.

## Most Important Python Functions

Below are the four most important Python Function that you should know:

1. Lambda Function
2. Map Function
3. Reduce Function
4. Filter Function

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#### Lambda Function:

An anonymous, built-in function is defined with lambda. The lambda parameters are defined to the left of the colon. The body of the function is defined as the colon’s right. The result of executing the function body is (implicitly) returned:

```s=lambda x:x*x
s(2)```

#### Map Function:

The map function takes on a function and a collection of elements. It creates a new, empty collection, runs the function on each item in the original collection, and inserts each return value into the new collection. It returns the new collection.

Below is a simple map function that takes a list of names and returns a list of the lengths of those names:

```name_lengths = map(len, ["Mary", "Isla", "Sam"])
print(name_lengths)```

#### Reduce Function:

The reduce function takes a function and a collection of elements. It returns a value created by combining the elements. Below is a simple reduction function that returns the sum of all the elements in the collection:

```total = reduce(lambda a, x: a + x, [0, 1, 2, 3, 4])
print(total)```

#### Filter Function:

The filter function also takes a function and a collection. It returns a collection of each element for which the function returned True. For example:

```arr=[1,2,3,4,5,6]
[i for i in filter(lambda x:x>4,arr)]```

So Lambda, Map, Reduce and Filter functions in python are the most important functions that you should know how to use as a Python developer. I hope you liked this article on the most important python functions you need to know. Feel free to ask your valuable questions in the comments section below.

##### Aman Kharwal

Coder with the ♥️ of a Writer || Data Scientist | Solopreneur | Founder

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