Python | Ways to sort letters of string alphabetically

Given a string of letters, write a python program to sort the given string in an alphabetical order.

Example:

Input : PYTHON
Output : HNOPTY

Input : Geeks
Output : eeGks

Naive Method to sort letters of string alphabetically

Here we are converting the string into list and then finally sorting the entire list alphabet wise.

s ="GEEKSFORGEEKS"

li = []
l = len(s)
for i in range (0,l):
    li.append(s[i])


for i in range(0,l):
    for j in range(0,l):
        if li[i]<li[j]:
            li[i],li[j]=li[j],li[i]
j=""

for i in range(0,l):
    j = j+li[i]

print(j)

Output:

EEEEFGGKKORSS

Using sorted() with join() to sort letters of string alphabetically

Here we are converting the string into a sorted list and then finally joining them using join function.

# Python3 program to sort letters 
# of string alphabetically

def sortString(str):
    return ''.join(sorted(str))
    
# Driver code
str = 'PYTHON'
print(sortString(str))

Output:

HNOPTY

Using sorted() with accumulate() to sort letters of string alphabetically

Here we are importing accumulate from itertools module converting the string into a sorted list, and hence return the result

# Python3 program to sort letters 
# of string alphabetically
from itertools import accumulate

def sortString(str):
    return tuple(accumulate(sorted(str)))[-1]
    
# Driver code
str = 'PYTHON'
print(sortString(str))

Output:

HNOPTY

Using sorted() with reduce() to sort letters of string alphabetically

Another alternative is to use reduce() method. It applies a join function on the sorted list using '+' operator. 

# Python3 program to sort letters 
# of string alphabetically
from functools import reduce

def sortString(str):
    return reduce(lambda a, b : a + b, sorted(str))
    
# Driver code
str = 'PYTHON'
print(sortString(str))

Output:

HNOPTY

When string is in different cases -

Using sorted() with join() to sort letters of string alphabetically

Here we are converting the string into a sorted list and then finally joining them using the lambda functions.

# Python3 program to sort letters
# of string alphabetically
from itertools import accumulate

def sortString(str):
    return "".join(sorted(str, key = lambda x:x.lower()))
    
# Driver code
str = 'Geeks'
print(sortString(str))

Output:

eeGks

Time Complexity: O(n*logn), as sorted() function is used.
Auxiliary Space: O(n), where n is length of string.