20 Essential Python Tips You Need to Know

Source: https://medium.com

The readability and simplicity of Python are two major reasons for its popularity. This article introduces 20 commonly used Python tips to enhance code readability and help you save a lot of time. The tips below will be very useful in your daily coding practice.1. Reverse a String

Reverse a string using Python slicing:

# Reversing a string using slicing

my_string = "ABCDE"
reversed_string = my_string[::-1]

print(reversed_string)

# Output
# EDCBA

2. Capitalize the First Letter of Each Word

Use the title function method:

my_string = "my name is chaitanya baweja"

# using the title() function of string class
new_string = my_string.title()

print(new_string)

# Output
# My Name Is Chaitanya Baweja

3. Find Unique Elements in a String

Use the concept of sets to find unique elements in a string:

my_string = "aavvccccddddeee"

# converting the string to a set
temp_set = set(my_string)

# stitching set into a string using join
new_string = ''.join(temp_set)

print(new_string)

# output
# cdvae

4. Repeat Printing a String and List n Times

You can use the multiplication symbol (*) to print a string or list multiple times:

n = 3 # number of repetitions

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]

5. List Comprehension

# Multiplying each element in a list by 2

original_list = [1,2,3,4]

new_list = [2*x for x in original_list]

print(new_list)
# [2,4,6,8]

6. Variable Swap

a = 1
b = 2

a, b = b, a

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

7. Split a String into a List of Substrings

Use the .split() function:

string_1 = "My name is Chaitanya Baweja"
string_2 = "sample/ string 2"

# default separator ' '
print(string_1.split())
# ['My', 'name', 'is', 'Chaitanya', 'Baweja']

# defining separator as '/'
print(string_2.split('/'))
# ['sample', ' string 2']

8. Combine Multiple Strings into One String

list_of_strings = ['My', 'name', 'is', 'Chaitanya', 'Baweja']

# Using join with the comma separator
print(','.join(list_of_strings))

# Output
# My,name,is,Chaitanya,Baweja

9. Check if a String is a Palindrome

my_string = "abcba"

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

# Output
# palindrome

10. Count the Occurrences of Elements in a List

# finding frequency of each element in a list
from collections import Counter

my_list = ['a','a','b','b','b','c','d','d','d','d','d']
count = Counter(my_list) # defining a counter object

print(count) # Of all elements
# Counter({'d': 5, 'b': 3, 'a': 2, 'c': 1})

print(count['b']) # of individual element
# 3

print(count.most_common(1)) # most frequent element
# [('d', 5)]

11. Check if Two Strings are Anagrams

Anagrams mean that each word contains the same number of occurrences of each letter (case insensitive). Use the Counter class to check if two strings are anagrams.

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')

# output
# 1 and 2 anagram

12. Use try-except-else Block for Exception Handling

Use except for exception handling:

a, b = 1,0

try:
    print(a/b)
    # exception raised when b is 0
except ZeroDivisionError:
    print("division by zero")
else:
    print("no exceptions raised")
finally:
    print("Run this always")

# output
# division by zero
# Run this always

13. Use the enumerate Function to Get Key/Value Pairs

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

14. Check Memory Usage of an Object

import sys

num = 21

print(sys.getsizeof(num))

# In Python 2, 24
# In Python 3, 28

15. Merge Dictionaries

dict_1 = {'apple': 9, 'banana': 6}
dict_2 = {'banana': 4, 'orange': 8}

combined_dict = {**dict_1, **dict_2}

print(combined_dict)
# Output
# {'apple': 9, 'banana': 4, 'orange': 8}

16. Measure Execution Time of a Code Block

Use the time class to measure the time taken to execute a piece of code:

import time

start_time = time.time()
# Code to check follows
for i in range(10**5):
    a, b = 1,2
    c = a+ b
# Code to check ends
end_time = time.time()
time_taken_in_micro = (end_time- start_time)*(10**6)

print(time_taken_in_micro)

# output
# 18770.217895507812

17. Flatten a List

from iteration_utilities import deepflatten

# if you only have one depth nested_list, use this
def flatten(l):
  return [item for sublist in l for item in sublist]

l = [[1,2,3],[3]]
print(flatten(l))
# [1, 2, 3, 3]

# if you don't know how deep the list is nested
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]

18. Sample from a List

import random

my_list = ['a', 'b', 'c', 'd', 'e']
num_samples = 2

samples = random.sample(my_list,num_samples)
print(samples)
# [ 'a', 'e'] this will have any 2 random values

19. Convert an Integer to a List of Digits

Convert an integer into a list of digits:

num = 123456

# using map
list_of_digits = list(map(int, str(num)))

print(list_of_digits)
# [1, 2, 3, 4, 5, 6]

# using list comprehension
list_of_digits = [int(x) for x in str(num)]

print(list_of_digits)
# [1, 2, 3, 4, 5, 6]

20. Check for Unique Elements in a List

Check if each element in a list is unique:

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

—END—



Disclaimer: Some content is sourced from the internet for academic exchange purposes only. The copyright of the article belongs to the original author. If there are any issues, please contact for removal.