Replacing Characters in String: first one character replaces with string then another character with another string

Question

If i start with a string called x for N=0 , that is

x="G"

Then if I have a range N , that is 1 , I want to replace G from x with SRGRS , so that

x1="SRGRS"

Then if N=2, I want to replace S in x1 with GLSLG and G with SRGRS , so that I get

x2="GLSLGRSRGRSRGLSLG"

and then continue with N+=1, I'm replacing "G" and "S" from x2 with the corresponding string..

how do I write a loop, that does this continuously?

I've tried to use str.replace() , but I can't it to work :(

edit: in the loop: If there is "G"in the string, it should be replaced with "SRGRS" If there is "S" in the string, it should be replaced with "GLSLG"

Answer 1

For nbIter iterations, replaces simultaneously "S" by "GLSLG" and "G" by "SRGRS".

nbIter=4
x="G"
print(x)

for i in range(nbIter):
    newX=""
    for char in x:
        if char=="S":
            newX+="GLSLG"
        elif char=="G":
            newX+="SRGRS"
        else:
            newX+=char
    x=newX
    print(x)