String slicing and loop iteration

[divyansh]

string="demoString"
for ch in string:
    print(ch)    # this for loop will post a single character
#current outpput
#d
#e
#m
#o
#S
#t
#r
#i
#n
#g

''' my question is how to have sub-strings in output by the same functional loop (i mean is their any way to fill ch with a sub-string instead of just a single character (same functional loop mean can we use slicing for having a the sub-string-> 
 for ch in string[::3]: # i know this will not work but i am giving you a reference for the loop 
    <expresion>)
'''
# desired output if sub string length is 3 ->
#dem
#oSt
#rin
#g