Let us see how to repeat all elements of the given array of string 3 times. Example :
Input : [‘Akash’, ‘Rohit’, ‘Ayush’, ‘Dhruv’, ‘Radhika’] Output : [‘AkashAkashAkash’, ‘RohitRohitRohit’, ‘AyushAyushAyush’, ‘DhruvDhruvDhruv’, ‘RadhikaRadhikaRadhika’]
We will be using the numpy.char.multiply(a, i) method for this task.
numpy.char.multiply(a, i)
Syntax : numpy.char.multiply(a, i) Parameters :
- a : array of str or unicode
- i : number of times to be repeated
Returns : Array of strings
Example 1 : Repeating 3 times.
Python3
# importing the moduleimport numpy as np# created array of stringsarr = np.array(['Akash', 'Rohit', 'Ayush', 'Dhruv', 'Radhika'], dtype = np.str)print("Original Array :")print(arr)# with the help of np.char.multiply()# repeating the characters 3 timesnew_array = np.char.multiply(arr, 3)print("\nNew array :")print(new_array) |
Output :
Original Array : [‘Akash’ ‘Rohit’ ‘Ayush’ ‘Dhruv’ ‘Radhika’] New array : [‘AkashAkashAkash’ ‘RohitRohitRohit’ ‘AyushAyushAyush’ ‘DhruvDhruvDhruv’ ‘RadhikaRadhikaRadhika’]
Time complexity: O(n), where n is the length of the input array
Auxiliary space: O(n).
Example 2: Repeating 2 times.
Python3
# importing the moduleimport numpy as np# created array of stringsarr = np.array(['Geeks', 'for', 'Geeks'])print("Original Array :")print(arr)# with the help of np.char.multiply()# repeating the characters 3 timesnew_array = np.char.multiply(arr, 2)print("\nNew array :")print(new_array) |
Output :
Original Array : ['Geeks' 'for' 'Geeks'] New array : ['GeeksGeeks' 'forfor' 'GeeksGeeks']
Time complexity: O(n), where n is the number of characters in the original array.
Auxiliary space: O(n), where n is the number of characters in the original array.
EXAMPLE 3 – Method 2: We can use a list comprehension to repeat each string in the array multiple times .
Python3
# importing the moduleimport numpy as np# created array of stringsarr = np.array(['Geeks', 'for', 'Geeks'])print("Original Array :")print(arr)# using list comprehension to repeat each string in the arrayn = 2 # number of times to repeat each stringnew_array = np.array([s * n for s in arr])print("\nNew array :")print(new_array) |
OUTPUT-
Original Array :
[‘Geeks’ ‘for’ ‘Geeks’]
New array :
[‘GeeksGeeks’ ‘forfor’ ‘GeeksGeeks’]
Time complexity: O(n * k), where n is the length of the input array and k is the number of times each string is repeated.
Auxiliary space: O(n), as we create a new list of length n to store the repeated strings. However, this is not counting the space needed for the input and output arrays.
