Useful Python Code Snippets for Everyday Tasks

String reversal

Reverse a string using slicing.

# Reversing a string using slicing
my_string = "ABCDE"
reversed_string = my_string[::-1]
print(reversed_string)  # Output: EDCBA

Title case

Capitalize the first letter of each word using the title() method.

my_string = "my name is chaitanya baweja"
new_string = my_string.title()
print(new_string)  # Output: My Name Is Chaitanya Baweja

Extract unique characters

Convert a string to a set to obtain distinct characters and join them back.

my_string = "aavvccccddddeee"
temp_set = set(my_string)
new_string = ''.join(temp_set)
print(new_string)  # Output: acedv (order may vary)

Repeat strings and lists

Use multiplication to repeat a string or list.

n = 3
my_string = "abcd"
my_list = [1, 2, 3]
print(my_string * n)  # abcdabcdabcd
print(my_list * n)    # [1, 2, 3, 1, 2, 3, 1, 2, 3]

List of constant length

n = 4
my_list = [0] * n  # [0, 0, 0, 0]

List comprehension

Multiply each element by 2 using a list comprehension.

original_list = [1, 2, 3, 4]
new_list = [2 * x for x in original_list]
print(new_list)  # [2, 4, 6, 8]

Swap two variables

a = 1
b = 2
a, b = b, a
print(a)  # 2
print(b)  # 1

String splitting

string_1 = "My name is Chaitanya Baweja"
print(string_1.split())  # ['My', 'name', 'is', 'Chaitanya', 'Baweja']
string_2 = "sample/ string 2"
print(string_2.split('/'))  # ['sample', ' string 2']

String joining

list_of_strings = ['My', 'name', 'is', 'Chaitanya', 'Baweja']
print(','.join(list_of_strings))  # My,name,is,Chaitanya,Baweja

Palindrome detection

my_string = "abcba"
if my_string == my_string[::-1]:
    print("palindrome")
else:
    print("not palindrome")

Counting element frequencies

from collections import Counter
my_list = ['a','a','b','b','b','c','d','d','d','d','d']
count = Counter(my_list)
print(count)               # Counter({'d': 5, 'b': 3, 'a': 2, 'c': 1})
print(count['b'])         # 3
print(count.most_common(1))# [('d', 5)]

Anagram checking with Counter

from collections import Counter
str_1, str_2, str_3 = "acbde", "abced", "abcda"
cnt_1, cnt_2, cnt_3 = Counter(str_1), Counter(str_2), Counter(str_3)
if cnt_1 == cnt_2:
    print('1 and 2 anagram')
if cnt_1 == cnt_3:
    print('1 and 3 anagram')

Exception handling with try‑except‑else‑finally

a, b = 1, 0
try:
    print(a / b)
except ZeroDivisionError:
    print("division by zero")
else:
    print("no exceptions raised")
finally:
    print("Run this always")

Enumerate over a list

my_list = ['a', 'b', 'c', 'd', 'e']
for index, value in enumerate(my_list):
    print('{0}: {1}'.format(index, value))
# 0: a
# 1: b
# 2: c
# 3: d
# 4: e

Object memory size

import sys
num = 21
print(sys.getsizeof(num))  # 28 in Python 3

Merge two dictionaries

dict_1 = {'apple': 9, 'banana': 6}
dict_2 = {'banana': 4, 'orange': 8}
combined_dict = {**dict_1, **dict_2}
print(combined_dict)  # {'apple': 9, 'banana': 4, 'orange': 8}

Measure code execution time

import time
start_time = time.time()
# code to measure
a, b = 1, 2
c = a + b
end_time = time.time()
time_taken_in_micro = (end_time - start_time) * (10**6)
print("Time taken in micro_seconds: {0} ms".format(time_taken_in_micro))

Flatten nested lists

from iteration_utilities import deepflatten
l = [[1,2,3],[3]]
print([item for sublist in l for item in sublist])  # [1,2,3,3]
# Deep flatten with unknown depth
l = [[1,2,3],[4,[5]],[6,7]],[[8],[9,[10]]]]
print(list(deepflatten(l, depth=3)))  # [1,2,3,4,5,6,7,8,9,10]

Random sampling

import random
my_list = ['a','b','c','d','e']
num_samples = 2
samples = random.sample(my_list, num_samples)
print(samples)

Secure random sampling

import secrets
secure_random = secrets.SystemRandom()
my_list = ['a','b','c','d','e']
num_samples = 2
samples = secure_random.sample(my_list, num_samples)
print(samples)

Convert integer to list of digits

num = 123456
list_of_digits = list(map(int, str(num)))
print(list_of_digits)  # [1, 2, 3, 4, 5, 6]

Check list uniqueness

def unique(l):
    if len(l) == len(set(l)):
        print("All elements are unique")
    else:
        print("List has duplicates")
unique([1,2,3,4])   # All elements are unique
unique([1,1,2,3])   # List has duplicates

These snippets were gathered from daily work and aim to provide quick, reusable solutions for common Python tasks.