# Python – Consecutive Repetition of Characters

Sometimes, while working with character lists we can have a problem in which we need to perform consecutive repetition of characters. This can have application in many domains. Lets discuss certain ways in which this task can be performed.

Method #1 : Using list comprehension
This is one of the way in which this task can be performed. In this, we perform a brute force way to perform but in a one-liner for by multiplying each character by magnitude.

 `# Python3 code to demonstrate working of  ` `# Consecutive Repetition of  Characters ` `# Using list comprehension ` ` `  `# initializing list ` `test_list ``=` `[``'g'``, ``'f'``, ``'g'``, ``'i'``, ``'s'``, ``'b'``, ``'e'``, ``'s'``, ``'t'``] ` ` `  `# printing original list ` `print``(``"The original list is : "` `+` `str``(test_list)) ` ` `  `# initializing K  ` `K ``=` `3` ` `  `# Consecutive Repetition of  Characters ` `# Using list comprehension ` `res ``=` `[sub ``for` `ele ``in` `test_list ``for` `sub ``in` `[ele] ``*` `K] ` ` `  `# printing result  ` `print``(``"The list after Consecutive Repetition is : "` `+` `str``(res))  `

Output :

The original list is : [‘g’, ‘f’, ‘g’, ‘i’, ‘s’, ‘b’, ‘e’, ‘s’, ‘t’]
The list after Consecutive Repetition is : [‘g’, ‘g’, ‘g’, ‘f’, ‘f’, ‘f’, ‘g’, ‘g’, ‘g’, ‘i’, ‘i’, ‘i’, ‘s’, ‘s’, ‘s’, ‘b’, ‘b’, ‘b’, ‘e’, ‘e’, ‘e’, ‘s’, ‘s’, ‘s’, ‘t’, ‘t’, ‘t’]

Method #2 : Using `chain() + repeat()`
The combination of above functions can be used to solve this problem. In this, we perform the task of repeating using repeat() and the result construction using chain().

 `# Python3 code to demonstrate working of  ` `# Consecutive Repetition of  Characters ` `# Using chain() + repeat() ` `from` `itertools ``import` `chain, repeat ` ` `  `# initializing list ` `test_list ``=` `[``'g'``, ``'f'``, ``'g'``, ``'i'``, ``'s'``, ``'b'``, ``'e'``, ``'s'``, ``'t'``] ` ` `  `# printing original list ` `print``(``"The original list is : "` `+` `str``(test_list)) ` ` `  `# initializing K  ` `K ``=` `3` ` `  `# Consecutive Repetition of  Characters ` `# Using chain() + repeat() ` `res ``=` `list``(chain.from_iterable(repeat(``chr``, K) ``for` `chr` `in` `test_list)) ` ` `  `# printing result  ` `print``(``"The list after Consecutive Repetition is : "` `+` `str``(res))  `

Output :

The original list is : [‘g’, ‘f’, ‘g’, ‘i’, ‘s’, ‘b’, ‘e’, ‘s’, ‘t’]
The list after Consecutive Repetition is : [‘g’, ‘g’, ‘g’, ‘f’, ‘f’, ‘f’, ‘g’, ‘g’, ‘g’, ‘i’, ‘i’, ‘i’, ‘s’, ‘s’, ‘s’, ‘b’, ‘b’, ‘b’, ‘e’, ‘e’, ‘e’, ‘s’, ‘s’, ‘s’, ‘t’, ‘t’, ‘t’]

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