Popular Functions in Python

Overview:

Python functions are pieces of code that can be reused and passed around. They are utilized to break down an expansive program into littler chunks, making it less demanding to debug and keep up. Functions are declared using the def keyword and can take optional parameters. They can also return values utilizing the return keyword. Functions can be used to perform assignments such as calculations, string manipulations, and file operations. Also, functions can be used to make classes and modules.

What are some popular functions in Python

1. print: prints a specified message to the screen

print("Hello World")  # Output: Hello World

Hello world message is printed here

2. type: 1. returns the type of an object

 x = 10
print(type(x))  # Output: <class 'int'>

x=10 is taken, and input and its type int is returned

3. input: reads a line of input from the user

x = input("Enter a number: ")  # Output: Enter a number:

The number is inputted here

4. abs: returns the absolute value of a number

print(abs(-90))  # Output: 90

An absolute value of -90 is returned, which is 90

5. pow: returns the result of a number raised to a specified power

pow(2, 3)  # Output: 8

The power of 2^3, which is 8, is returned

6. sorted: returns a sorted list of elements

sorted([2, 3, 1, 4, 5])  # Output: [1, 2, 3, 4, 5]

The list of values is sorted

7. max: returns the largest element in an iterable object

max(2, 10, -5)  # Output: 10

The maximum of the list, which is 10, is returned

8. round: rounds a number to a specified number of decimal places

round(3.14159)  # Output: 3

It rounds off the value and returns 3

9. id:  returns the identity of an object

id(10)  # Output: 140735457659248

The identity of 10 is returned

10. ord: returns the Unicode code point for a character

ord('a')  # Output: 97

Ascii code of a is returned

11. len:  returns the length of an object

len('Hello World')  # Output: 11

The length of the message is displayed

12. sum: returns the sum of the items of an iterable object

sum([2, 4, 6, 8])  # Output: 20

The sum of the list is returned

13. help: prints information about a specified object

help()  # Output: help>

For any help or information, this is used

14. Lambda: creates an anonymous function

Lambda x: x + 1  # Output: <function <lambda> at 0x0000020F2F35EAE8>

The lambda function takes in a single argument (x) and adds 1 to it.

15. Map: applies a function to all the items of an iterable object

Map(lambda x: x + 1, [1, 2, 3, 4])  # Output: <map object at 0x0000020F2F35E9E8>

The map function takes in a function (in this case the lambda function) and an iterable (in this case a list of numbers [1,2,3,4]) and applies the function to each element of the iterable and returns a map object.

16. Filter: creates a list of elements for which a function returns true

Filter(lambda x: x > 2, [1, 2, 3, 4])  # Output: <filter object at 0x

The map function takes in a function (in this case, the lambda function) and an iterable (in this case, a list of numbers [1,2,3,4]) and applies the function to each element of the iterable, and returns a map object.

17. Enumerate: adds a counter to an iterable object.

my_list = ["apple", "banana", "cherry"]
for index, item in enumerate(my_list):
  print(index, item)

# Output:
# 0 apple
# 1 banana
# 2 cherry

The enumerate function takes an iterable (in this case, a list of strings ["apple", "banana", "cherry"]). It returns an enumerate object, which contains the index and value of each iterable element.

18. Eval: evaluates a string as a Python expression

x = 1
y = 2
eval('x + y')  # Output: 3

The eval function takes a string as input and evaluates it, returning the result.

19. Range: generates a sequence of numbers within a specified range

list(range(1, 10))  # Output: [1, 2, 3, 4, 5, 6, 7, 8, 9]

The range function takes in two numbers (in this case, 1 and 10) and returns a range object containing the numbers between the two numbers (in this case, 1, 2, 3, 4, 5, 6, 7, 8, 9).

20. Groupby: is used to split the data into groups based on some criteria.

# Grouping data based on 'Team' 
import pandas as pd 

# Initialize dataframe 
df = pd.DataFrame({'Team': ['A','B','C','A','B','C','A','B','C'], 
                   'Score': [1,2,3,4,5,6,7,8,9]}) 

# Group data based on 'Team'
df_grouped = df.groupby('Team')

# Print the grouped data
print(df_grouped)

This code uses the groupby() function from the pandas library to group the data in the dataframe df based on the 'Team' column. The result of the groupby() function is stored in the df_grouped dataframe. Finally, the grouped data is printed to the console.

Conclusion

We found how these built-in functions can perform different assignments, from fundamental arithmetic to complex database operations. We learned how to create our functions and call them in her code. Along the way, we tested distinctive methods to improve the code, such as looping and nesting. As we continued to investigate and practice, we begun to gain a more profound understanding of Python and its capabilities.

Key takeaways

1. Built-in functions are pre-defined, standardized functions available in most programming languages.
2. They can save time and effort when coding, as they are already written and tested.
3. Built-in functions are often optimized for performance, which can improve the speed of your code.
4. Built-in functions can perform complex operations in a single line of code.
5. Built-in functions are often well-documented and easy to use, making them ideal for beginners.
6. Built-in functions can be used to manipulate data, perform calculations, and more.
7. It is important to understand the arguments and parameters of a built-in function before using it.

Quiz

1. What is the purpose of a function in Python?
   1.  To provide a way to structure programs into logical units
   2. To execute a block of code multiple times
   3. To create a variable
   4. To perform mathematical operations

Answer:a. To provide a way to structure programs into logical units

2. What is the purpose of the sorted() function in Python? 
   1. To sort a list of elements 
   2. To convert a list to a dictionary  
   3. To find the length of a string 
   4. To create a new list

Answer:a. To sort a list of elements

3. What is the purpose of the len() function in Python?  
   1. To sort a list of elements 
   2. To convert a list to a dictionary 
   3. To find the length of a string 
   4. To create a new list

Answer:c. To find the length of a string

4. What is the purpose of the dict() function in Python? 
   1. To sort a list of elements
   2. To convert a list to a dictionary 
   3. To find the length of a string  
   4. To create a new list

Answer:b. To convert a list to a dictionary