22 Useful Python Code Examples: From Manipulating Strings to Sorting Lists

22 Useful Python Code Examples: From Manipulating Strings to Sorting Lists

Python is a versatile programming language that is widely used for various tasks. In this article, we will explore 22 useful code examples that harness the power of Python. Some of these examples may be familiar to you, while others may introduce new and interesting concepts. These examples are easy to remember and can be applied in your own projects. Let's dive in!

1. Getting Vowels
   This example returns the vowels found in a given string. It can be useful for searching or detecting vowels in a text.

def get_vowels(string):  
    return [each for each in string if each in "aeiou"]  
  
get_vowels("animal")   ['a', 'i', 'a']  
get_vowels("sky")   []  
get_vowels("football")   ['o', 'o', 'a']  

2. Capitalizing the First Letter
   This example converts the first letter of each word in a string to uppercase. It can be handy for text analysis or data recording.

def capitalize(string):  
    return string.title()  
  
capitalize("shop")   'Shop'  
capitalize("python programming")   'Python Programming'  
capitalize("how are you!")   'How Are You!'  

3. Printing a String Multiple Times
   This example prints a given string multiple times without using loops in Python.

n = 5  
string = "Hello World "  
print(string * n)  
 Output: Hello World Hello World Hello World Hello World Hello World  

4. Merging Two Dictionaries
   This example merges two dictionaries into one.

def merge(dic1, dic2):  
    dic3 = dic1.copy()  
    dic3.update(dic2)  
    return dic3  
  
dic1 = {1: "hello", 2: "world"}  
dic2 = {3: "Python", 4: "Programming"}  
merge(dic1, dic2)   {1: 'hello', 2: 'world', 3: 'Python', 4: 'Programming'}  

5. Calculating Execution Time
   This example is useful when you need to know how much time it takes to execute a program or function.

import time  
  
start_time = time.time()  
  
def fun():  
    a = 2  
    b = 3  
    c = a + b  
  
end_time = time.time()  
fun()  
timetaken = end_time - start_time  
print("Your program takes:", timetaken)  
 Output: Your program takes: 0.0345  

6. Swapping Variable Values
   This example provides a quick way to swap the values of two variables without using a third variable.

a = 3  
b = 4  
a, b = b, a  
print(a, b)   Output: a = 4, b = 3  

7. Checking for Duplicates in a List
   This example is the fastest way to check for duplicate values in a list.

def check_duplicate(lst):  
    return len(lst) != len(set(lst))  
  
check_duplicate([1, 2, 3, 4, 5, 4, 6])   True  
check_duplicate([1, 2, 3])   False  
check_duplicate([1, 2, 3, 4, 9])   False  

8. Filtering False Values
   This example is used to remove all false values from a list, such as False, 0, None, or an empty string.

def filtering(lst):  
    return list(filter(None, lst))  
  
lst = [None, 1, 3, 0, "", 5, 7]  
filtering(lst)   [1, 3, 5, 7]  

9. Calculating Byte Size
   This example returns the length of a string in bytes, which is useful when you need to know the size of a string variable.

def byte_size(string):  
    return len(string.encode("utf8"))  
  
byte_size("Python")   6  
byte_size("Data")   4  

10. Checking Memory Usage
    This example allows you to get the memory usage of any variable in Python.

import sys  
  
var1 = "Python"  
var2 = 100  
var3 = True  
  
print(sys.getsizeof(var1))   55  
print(sys.getsizeof(var2))   28  
print(sys.getsizeof(var3))   28  

11. Checking for Anagrams
    This code is useful for checking whether a string is an anagram. An anagram is a word formed by rearranging the letters of another word.

from collections import Counter  
  
def anagrams(str1, str2):  
    return Counter(str1) == Counter(str2)  
  
anagrams("abc1", "1bac")   True  

12. Sorting a List
    This example sorts a list. Sorting is a common task that can be implemented with a loop, but you can speed up your work using the built-in sort method.

my_list = ["leaf", "cherry", "fish"]  
my_list1 = ["D", "C", "B", "A"]  
my_list2 = [1, 2, 3, 4, 5]  
  
my_list.sort()   ['cherry', 'fish', 'leaf']  
my_list1.sort()   ['A', 'B', 'C', 'D']  
print(sorted(my_list2, reverse=True))   [5, 4, 3, 2, 1]  

13. Sorting a Dictionary
    This example sorts a dictionary by its values.

orders = {  
    'pizza': 200,  
    'burger': 56,  
    'pepsi': 25,  
    'Coffee': 14  
}  
  
sorted_dic = sorted(orders.items(), key=lambda x: x[1])  
print(sorted_dic)  
 Output: [('Coffee', 14), ('pepsi', 25), ('burger', 56), ('pizza', 200)]  

14. Getting the Last Element of a List
    This example demonstrates two methods to get the last element of a list.

my_list = ["Python", "JavaScript", "C++", "Java", "C", "Dart"]  
  
 Method 1  
print(my_list[-1])   Output: Dart  
  
 Method 2  
print(my_list.pop())   Output: Dart  

15. Converting a Comma-Separated List to a String
    This code converts a comma-separated list into a single string. It is handy when you need to concatenate a list with a string.

my_list1 = ["Python", "JavaScript", "C++"]  
my_list2 = ["Java", "Flutter", "Swift"]  
  
 Example 1  
print("My favourite Programming Languages are", ", ".join(my_list1))  
 Output: My favourite Programming Languages are Python, JavaScript, C++  
  
 Example 2  
print(", ".join(my_list2))  
 Output: Java, Flutter, Swift  

16. Checking for Palindromes
    This example quickly checks for the presence of palindromes.

def palindrome(data):  
    return data == data[::-1]  
  
palindrome("level")   True  
palindrome("madaa")   False  

17. Shuffling a List
    This example shuffles the elements of a list.

from random import shuffle  
  
my_list1 = [1, 2, 3, 4, 5, 6]  
my_list2 = ["A", "B", "C", "D"]  
  
shuffle(my_list1)   [4, 6, 1, 3, 2, 5]  
shuffle(my_list2)   ['A', 'D', 'B', 'C']  

18. Converting a String to Upper and Lower Case
    This example converts a string to uppercase and lowercase.

str1 = "Python Programming"  
str2 = "IM A PROGRAMMER"  
  
print(str1.upper())   PYTHON PROGRAMMING  
print(str2.lower())   im a programmer  

19. Formatting a String
    This code allows you to format a string by adding data from variables.

 Example 1  
str1 = "Python Programming"  
str2 = "I'm a {}".format(str1)  
 Output: I'm a Python Programming  
  
 Example 2 (using f-string)  
str1 = "Python Programming"  
str2 = f"I'm a {str1}"  
 Output: I'm a Python Programming  

20. Searching for Substrings
    This example will help you search for substrings in a string. I will demonstrate two methods that allow you to write less code.

programmers = [  
    "I'm an expert Python Programmer",  
    "I'm an expert Javascript Programmer",  
    "I'm a professional Python Programmer",  
    "I'm a beginner C++ Programmer"  
]  
  
 Method 1  
for p in programmers:  
    if p.find("Python"):  
        print(p)  
  
 Method 2  
for p in programmers:  
    if "Python" in p:  
        print(p)  

21. Printing on the Same Line
    By default, the print function outputs each string on a new line. This example shows how to print on the same line without a line break.