# Lecture: Learning Python 5-Functions ver. 1

Last Updated on July 9, 2022 by shibatau

The link to Python 6-If Statements is added.

## I. What will you learn?

These posts are Python tutorials for beginners and used for my lectures.

Learning Python 0-Cheat Sheets

Learning Python 1-Google Colaboratory

Learning Python 2-Sample data

Learning Python 3-Lists and Comprehensions

Learning Python 4-Dictionaries and Data frames

Learning Python 5-Functions

Learning Python 6-If Statements

Learning Python 7-For Loops

Learning Python 8-Classes and Objects

## II. Functions

There are three types of functions in Python:

• Built-in functions: you can find an overview with them here.
• User-Defined Functions (UDFs)
• Anonymous functions (Lambda functions): they are not declared with the standard def keyword.

Here are sample scripts in Cheat Sheets Basics V:

Define a function
def plus(a, b):
return a + b
Lambda functions
plus = lambda a, b: a + b
plus(10, 20)
# 30
Enumerate
ls = ['a', 'c', 'b']
print(list(enumerate(ls)))
# [(0, 'a'), (1, 'c’), (2, 'b')]
Sort
sorted(ls)
# ['a', 'b', 'c']
Reverse
list(reversed(ls))
Map
ls = ['abc', 'def']
list(map(lambda x: x.upper(), ls))
# ['ABC', 'DEF']
Reduce
from functools import reduce
ls = [10, 20, 30]
total = reduce(lambda a, b: a + b, ls)
total
# 60 

You can see the scripts here: 