# Python Tips and Tricks for Competitive Programming

• Difficulty Level : Basic
• Last Updated : 19 Aug, 2021

Python Programming language makes everything easier and straightforward. Effective use of its built-in libraries can save a lot of time and help with faster submissions while doing Competitive Programming. Below are few such useful tricks that every Pythonist should have at their fingertips:

• Converting a number into a List of digits using map() Function:

Below is the implementation to convert a given number into a list of digits:

## Python3

 `# Python program to convert a` `# number to a list of digits`   `# Given number` `n ``=` `123456`   `# Stores the list of digits` `lis ``=` `list``(``map``(``int``, ``str``(n)))`   `# Print the digits` `print``(lis)`

Output:

`[1, 2, 3, 4, 5, 6]`

• Converting a sentence into a List of words using split() Function: Below is the implementation to convert a sentence into a list of words:

## Python3

 `# Python program to convert` `# a sentence to a list of words`   `# Given sentence` `sentence ``=` `"GeeksforGeeks is the computer science portal for geeks"`   `# Convert the sentence` `# into a list of words` `lis ``=` `list``(sentence.split())`   `# Print the list of words` `print``(lis)`

Output:

`['GeeksforGeeks', 'is', 'the', 'computer', 'science', 'portal', 'for', 'geeks']`

• Take newline-separated integers as a List: Newline-separated input from the console can be taken in the form of a List using List Comprehension. Below is the implementation to take input of newline-separated integers as a list:

## Python3

 `# Python program to take` `# newline-separated input` `# in the form of a list`   `# Given input` `n ``=` `int``(``input``())`   `lis ``=` `[``int``(``input``()) ``for` `_ ``in` `range``(n)]`

Below is the implementation to demonstrate gcd() function:

## Python3

 `# Python program to demonstrate gcd() function` `import` `math` `a ``=` `8` `b ``=` `24`   `# Print the GCD of a and b` `print``(math.gcd(a, b))`

Output:

`8`

Below is the implementation of the approach:

## Python3

 `# Python program to print all` `# permutations using library function` `from` `itertools ``import` `permutations`   `# Get all permutations of [1, 2, 3]` `perm ``=` `permutations([``1``, ``2``, ``3``])`   `# Print the obtained permutations` `for` `i ``in` `list``(perm):` `    ``print` `(i)`

Output:

```(1, 2, 3)
(1, 3, 2)
(2, 1, 3)
(2, 3, 1)
(3, 1, 2)
(3, 2, 1)```

• Printing a string multiple times without Loop: Below is the implementation to print a string multiple times without loop using string multiplication technique:

## Python3

 `# Python program to print` `# a string given number of times`   `# Given string` `str` `=``"India"`   `# Print the string 2 times` `print``(``str` `*` `2``)`

Output:

`IndiaIndia`

• To print a list with spaces without loop: A list can be printed without running the loop by using the * operator in Python.

Below is the implementation to print a list with spaces without loop:

## Python3

 `# Python program to print a list with spaces without loop` `lis ``=` `[``1``, ``2``, ``3``, ``4``]`   `# Printing list elements with spaces` `print``(``*``lis)`

Output:

`1 2 3 4`

Below is the implementation of the above approach:

## Python3

 `# Python program to convert a` `# binary string to its decimal` `# equivalent using int() function`   `# Given string` `binary ``=` `"1010"`   `# Print decimal equivalent` `print``(``int``(binary, ``2``))`

Output

`10`
• To print sorted list with spaces: Sorting any sequence is very easy in Python using a built-in method sorted() and using * symbol to print list with spaces. Sorted() sorts any sequence (list, tuple) and always returns a list with the elements in a sorted manner, without modifying the original sequence.

Below is the implementation to print a sorted list with spaces:

## Python3

 `# Python program to print a sorted list with ` `# spaces using sorted() function` `lis ``=` `[``6``, ``2``, ``7``, ``3``, ``4``]`   `# Print the sorted sequence` `print``(``*``sorted``(lis))`

Output:

`2 3 4 6 7`

• To find common elements in two arrays: The common elements in 2 arrays/lists can be done in a much simpler way using sets. The intersection() function in Python gives the common elements in both arrays/lists.

Below is the implementation to demonstrate intersection() function:

## Python3

 `# Python program to print common elements in` `# both the list using intersection() function` `array1 ``=` `[``4``, ``5``, ``6``, ``7``, ``8``]` `array2 ``=` `[``3``, ``4``, ``5``, ``1``, ``72``]`   `# Print the common elements` `print``(``set``(array1).intersection(``set``(array2)))`

Output

`{4, 5}`

My Personal Notes arrow_drop_up
Recommended Articles
Page :