Python String Append Examples - Yudhy Network

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Yudhy Network - append string python. Here you will learn simple ways of how to append string to another string in python with examples or python append to string in loop.

Appending one string to another string in Python is a very easy task. In this python string post, you will learn how to append one string to another string.

Here we will append one string to another string by using the Python program. Let’s learn how to append the string in Python:

Python String Append

Python string object is immutable. So many time you use + operator to concatenate or join two strings in python programming and created a new string in python.

If you have to append many strings, using + operator will unnecessarily create many temporary strings before we have the final result.

Let’s look at a function to join a string ‘n’ times:

def str_append(s, n):
    output = ''
    i = 0
    while i < n:
        output += s
        i = i + 1
    return output

Notice:- that I am defining this function to showcase the usage of + operator. I will later use timeit module to test the performance. If you simply want to concatenate a string ‘n’ times, you can do it easily using s = 'Hi' * 10.

Another way to join/concatenate string append operation is by creating a python list and appending strings to the python list. Then use python string join() function to join/merge string and list together to get the result string.

def str_append_list_join(s, n):
    l1 = []
    i = 0
    while i < n:
        l1.append(s)
        i += 1
    return ''.join(l1)

Let’s examine these methods to make sure they are working as supposed.

if __name__ == "__main__":
    print('Append using + operator:', str_append('Hi', 10))
    print('Append using list and join():', str_append_list_join('Hi', 10))
    # use below for this case, above methods are created so that we can
    # check performance using timeit module
    print('Append using * operator:', 'Hi' * 10)

Output:

Append using + operator: HiHiHiHiHiHiHiHiHiHi
Append using list and join(): HiHiHiHiHiHiHiHiHiHi
Append using * operator: HiHiHiHiHiHiHiHiHiHi

A simple way to append strings in Python

You need to have both the methods defined in string_append.py file. Let’s use timeit module to check their performance.

$ python3.7 -m timeit --number 1000 --unit usec 'import string_append' 'string_append.str_append("Hello", 1000)' 
1000 loops, best of 5: 174 usec per loop
$ python3.7 -m timeit --number 1000 --unit usec 'import string_append' 'string_append.str_append_list_join("Hello", 1000)'
1000 loops, best of 5: 140 usec per loop

$ python3.7 -m timeit --number 1000 --unit usec 'import string_append' 'string_append.str_append("Hi", 1000)' 
1000 loops, best of 5: 165 usec per loop
$ python3.7 -m timeit --number 1000 --unit usec 'import string_append' 'string_append.str_append_list_join("Hi", 1000)'

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