This post will show some really awesome tricks in python.
Get the power of a number
Example, get 9^3 (9 to the power 3)
a ** b
5 ** 3
# 125Get square root of a number
num ** 0.5Tricks with print() method
print() method always put a new line character in the end. You can change that behavior as well
# ends with space
print(n, end=" ")
# ends with comma and a space
print(n, end=", ")Count occurrence of words in a string
def count_words(line):
result = {}
words = line.split()
for word in words:
result[word] = result.get(word, 0) + 1
return resultOr, a more better way to calculate count of words:
from collections import Counter
def count_words(line):
return Counter(line.split())Magic with Sequences
# Example array
a = [1, 2, 3, 4, 5]
# Get first element
a[0]
# Get last element
a[-1]
# Get element from 1st to 4th index
a[1:5]
# Get last 5 elements
a[-5:]
# First five elements
a[:5]
# Skip first 5 elements
a[5:]
# Get from index: 2 to 7, but skip by 2 index
a[2:8:2]
# Reverse copy of a list
a[::-1]
# Get even indexes starting from 1
a[1::2]Insert sub-array in between an array
a = [10, 20, 30, 40, 50]
# Insert [1, 2, 3, 4] after index=1
a[1:1] = 1, 2, 3, 4
print(a)
[10, 1, 2, 3, 4, 20, 30, 40, 50]Also, you can replace some indexes too
a = [10, 20, 30, 40, 50]
# Insert [1, 2, 3, 4] after index=2, and replace indexes=2,3
a[2:4] = 1, 2, 3, 4
print(a)
[10, 20, 1, 2, 3, 4, 50]Replace sequence of indexes to a single number
a[2:7] = 778
i.e. replace indexes=2, 3, 4, 5, 6 and insert number 778Insert in array at some position, and shift rest of array
Note: Above method replaces value at index specified. To just insert values, use below method
a = [10, 20, 30, 40, 50]
# Insert 90 at index=1
a.insert(1, 90)
print(a)
[10, 90, 20, 30, 40, 50]Find an Odd number
No, I’m not showing n%2==0 kind of method
a = [1, 2, 3, 4, 5]
[ v for v in a if v & 1 ]
print(a)
[1, 3, 5]Square of Odd numbers
a = [1, 2, 3, 4, 5]
[ v*v for v in a if v & 1 ]
print(a)
[1, 9, 25]Capitalize all names which starts with letter ‘r’ (for example)
users = ["virat kohli", "ajay jadeja", "rohit sharma", "ram sharma"]
[ n.capitalize() for n in users if n[0] in 'rR']
['Rohit sharma', 'Ram sharma']Create a dictionary of number and its square
a = [10, 20, 30]
{ v: v*v for v in a}
{10: 100, 20:400, 30:900}Get a tuple of square
a = [10, 20, 30]
tuple(x*x for x in a)
(100, 400, 900)
