python string slicing
Concept:
s[x:y:z] , x- left index , y-1 - right index
z is the number of steps of jumping between 2 chr
if z>0 :
direction of jump is right to left(R2L)
else:
direction of jump is left to right(L2R)
s[:3] means x=0,y=2,z=1
s[3:] means x=3,y=len(s)-1,z=1
examples:
s="dbdhdhndnbdd"
print(s[2:6:2])
//prints dd as left index is 2 right is 5 -> substring is dhdh & 2 means d,skip h,then d
s="djdjcjfd"
print(s[::-2])
//prints djjj, left index is 0 ,right is len(s)-1 -> substring is djdjcjfd &
//-2 means start from right side in substring in steps of 2-> d,skip f,then j,skip c,then j & j