pythonfor-looprangereversing

In this reverse range loop exercise not sure why the stop value is -1, shouldn't it be 0 in this start,stop,step range reverse exercise

string = input("Enter a string: ")

for i in range(len(string)-1, -1, -1):
    print(string[i], end="")

I am confused in this start, stop, step not sure why it is -1 in the stop bit - I tried putting 0.

Solution 
  • range(start, stop, step)

start: It is optional. default value is 0.
stop: It is required although the number defined in stop is not included [exclusive]
step: It is optional. default value is 1

    for i in range(len(string)-1, -1, -1): This will iterate from last character to first character

    for i in range(len(string)-1, 0, -1): This will iterate from last character to second character

    For better understanding:

    Ex- range(1,5)  -> 1,2,3,4         #5 is not included.
Ex- range(-9,-5) -> -9,-8,-7,-6    #-5 is not included.
Ex- range(8,3,-1) -> 8,7,6,5,4     #3 is not included.