Code and approach to solve Concatenation of array

class Solution:
    def getConcatenation(self, nums: List[int]) -> List[int]:
        ans = []

        for i in nums:
            ans.append(i)

        ans += nums

        return ans

PROBLEM

so in the ques we have given an array nums and we have to return the array with itself concatenated. like here nums = [1,2,3] so we have to return [1,2,3,1,2,3]. basically we have to put the same array two times one after another.

APPROACH

so here we first create a blank array ans where we will store the elements.

then we loop through nums and append every element into ans. after that ans already contains the original array.

then we use ans += nums which adds the complete nums array again at the end of ans.

so if nums = [1,2,3]:

ans = [1,2,3]

then ans += nums

ans = [1,2,3,1,2,3]

and finally we return ans.

CODE EXPLAINATION

nums = [1,2,3]

ans = []

creating a blank array to store the elements of nums.

for i in nums:
    ans.append(i)

-> looping through nums and adding every element into ans. So after this loop ans becomes [1,2,3].

ans += nums

-> adding the complete nums array again at the end of ans. So ans becomes [1,2,3,1,2,3].

return ans

-> returns the concatenated array [1,2,3,1,2,3].