Python string manipulation { _teststr[2:12:-1]) }-CodePudding

I just started learning Python, and I was just getting into strings. So I have 3 commands here

_teststr = "IneedToFocusOnMyFuture"
print('1.',_teststr[::-1])
print('2.',_teststr[2:12:2])
print('3.',_teststr[2:12:-1])

Output:

1. erutuFyMnOsucoFoTdeenI
2. edoou
3.

Why the 3rd output is blank instead of having 'uoode'? What is going under the hood? Could anyone please explain?

CodePudding user response：

if you want to reverse the specific string.

print('3.',_teststr[2:12][::-1])

Lets understand the syntax

str[start:end:step]

start denotes from where to splice and end denotes where to end the splice. The step parameter denotes the number of elements to leave after a successful splicing.By default step is 1.

Example:

str="naveen"
str[1:3] //av
#with including step
str[1:3:1] //av
str[1:4:2] //ae
step defines the number of elements to leave after a consideration.So it cant be negative.