Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Shuffle an Array in Python
Suppose we have an array A, we have to shuffle a set of numbers without duplicates. So if the input is like [1,2,3], then for shuffling, it will be [1,3,2], after resetting, if we shuffle again, it will be [2,3,1]
To solve this, we will follow these steps −
There will be different methods. these are init(), reset(), shuffle(). These will act like below −
init will be like −
original := a copy of the given array
temp := nums
indices := a list of numbers from 0 to length of nums – 1
the reset() will return the original array
the shuffle() will be like −
if length of temp is 0, then return empty array
i := choice randomly one index from indices array, j := choose another index from indices array randomly
swap the elements present at index i and j
return temp
another method called getAllPermutation() will take nums, i, initially i = 0, will be like −
curr := i
if i = length of nums, then
insert a copy of nums array into another array called all
return
for j := curr to length of nums
swap elements at index j and curr from nums
call getAllPermutation(nums, curr + 1)
swap elements at index j and curr from nums
Let us see the following implementation to get better understanding −
Example
import random class Solution(object): def __init__(self, nums): self.original = [x for x in nums] self.temp = nums self.indices = [x for x in range(len(nums))] def reset(self): return self.original def shuffle(self): if not len(self.temp): return [] i = random.choice(self.indices) j = random.choice(self.indices) self.temp[i], self.temp[j] = self.temp[j], self.temp[i] return self.temp ob = Solution([1,2,3]) print(ob.shuffle()) print(ob.reset()) print(ob.shuffle())
Input
Initialize with [1,2,3] , then call shuffle(), reset() and shuffle()
Output
[2, 1, 3] [1, 2, 3] [2, 3, 1]
1K+ Views
