As we know, inserting an item into a list is quite common, but sometimes we need to work with a list of strings, looking at each letter and inserting some repetitive items at a fixed frequency. Let’s see how to solve this problem with Python.
Method # 1: Using the enumerate () method
| # Python program to insert value after
# every k letters in the given list of strings list1 = [ ’ p’ , ’y’ , ’ t’ , ’h’ , ’ o’ , ’n’ ]
# print original list print ( "Original list:" + str (list1))
# initialization to k = ’ G’
# initialization N N = 2
# using join () + enumerate ()
# insert K after every Nth number output = list (’’ .join (i + k * < code class = "plain"> (N % 2 = = 1 ) for N, i in enumerate (list1)))
# print result print ( "The lists after insertion:" + str (output)) |
Output:
Original list: [’p’,’ y’, ’t’,’ h’, ’o’,’ n’] The lists after insertion: [’p’,’ y’, ’G’,’ t’, ’h’,’ G’, ’o’,’ n’, ’G’]
Method # 2: Used no itertools
| # Python program to insert value after
# every k letters in the given list lines from itertools import chain list1 = [ ’p’ , ’ y’ , ’t’ , ’h’ , ’o’ , ’ n’ ]
# print the original list print ( "Original list:" + str (list1))
# initialize to k = ’x’
# initialization N N = 3
# insert K after every Nth number output = list (chain ( * [list1 [i: i + N] + [k] if len (list1 [i: i + N]) = = N else list1 [i: i + N] for i in range ( 0 , len (list1), N)]))
# print result print ( "The lists after insertion:" + str (output)) |
Exit:
Original list: [’p’,’ y’, ’t’,’ h’, ’o’,’ n’] The lists after insertion: [’p’,’ y’, ’t’,’ x’, ’h’ , ’o’,’ n’, ’x’]
