Useful Python snippets

Its handy to have a collection of useful little snippets when you are using any programming language. This is ours for python– work in progress as we various of them we have used over the years

Reverse a string

#!/usr/bin/python
​
myString = "The string to be reversed" 
reverse_string = myString[::-1] 
print(reverse_string)

Is a number even or odd

#!/usr/bin/python

def is_even(num):
return num % 2 == 0

if (is_even(4)):
print("even number")
else:
print("odd number")

if (is_even(5)):
print("even number")
else:
print("odd number")

Get the frequency of elements in a list

#!/usr/bin/python

from collections import Counter
numberlist = [1, 2, 3, 2, 4, 3, 2, 3, 1, 2, 4, 3, 1, 2, 1, 3, 4, 1, 2]
count = Counter(numberlist)
print(count)

Average of a list of numbers

#!/usr/bin/python

def average(*args):
return sum(args, 0.0) / len(args)

print (average(5, 8, 2, 9, 7, 12, 6, 4))

print (average(2, 7, 3, 11, 4, 12, 8, 4))

Get the most frequent number in a list

#!/usr/bin/python

def most_frequent_number(list):
return max(set(list), key = list.count)

numbers = [1, 2, 3, 2, 4, 3, 2, 3, 1, 2, 4, 3, 1, 2, 1, 3, 4, 1, 2]

print (most_frequent_number(numbers))

Check for vowels in a a string

#!/usr/bin/python

def get_vowels(string):
return [each for each in string if each in 'aeiou']


print (get_vowels('A test string'))
print (get_vowels('myrrh'))

Is a string a palindrome

#!/usr/bin/python

def palindrome(a):
return a == a[::-1]

print (palindrome('anna'))
print (palindrome('anne'))

Shuffle a list

#!/usr/bin/python

from random import shuffle

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
shuffle(numbers) 
print(numbers)

Split a string into substrings

#!/usr/bin/python

string_1 = "This is a sample string to split up"
string_2 = "sample/ string / example/ number /2"

# separator ' '
print(string_1.split())

# separator as '/'
print(string_2.split('/'))

Combine a list of strings into one string

#!/usr/bin/python

list_of_strings = ['This', 'is', 'a', 'sample', 'string']

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