How to find character used in a string?

Question

input-aabcds
output-[a,b,c,d,s]

Answer 1

Look this

https://code.sololearn.com/crYOtj92fq32/?ref=app

Answer 2

A python version could be like this:
s = list(set(input("Give me some text\n")))
s.sort() #if sort is needed
print("This is the result: ", s)

Answer 3

java:
string.toCharArray();