Question

Look at the sequence and determine the output >>> str="Python" >>> str[:-1] A. 'nohtyP' B. 'nhy' C. 'nhyP' D. 'Pytho'​

Answer 1

String Slices

String Slicing in Python refers to the act of extracting a substring from a given string.

GIVEN PROGRAM:

>>> str = "Python"

>>> str[:-1]

OUTPUT:

$\texttt{'Pytho'}$

It selects all characters of the sequence but the last. It gets all the characters from the string but the last character. $\texttt{:}$ represents going through the string $\texttt{-1}$ implies the last character of the string.

The syntax of string slicing is given below:

$>>> \texttt{string-object[start : stop : steps]}$

Let's take an example to understand better.

$\begin{array}{l}\:0\:\:\:1\:\:\:2\:\:\:3\:\:\:4\:\:\:5\;\;\longrightarrow{\textsf{Positive indexing}}\\ \boxed{\tt P}\boxed{\tt Y}\boxed{\tt T}\boxed{\tt H}\boxed{\tt O}\boxed{\tt N}\\\text{-6}\:\text{-5}\: \text{-4}\:\:\text{-3}\:\text{-2}\:\:\text{-1}\;\;\longrightarrow{ \textsf{Negative indexing}}\end{array}$

str[1:5]

• str[1:5] is 'YTHO' - characters starting at index 1 and extending up to but not including index 5.

str[1:4]

• str[1:5] is 'YTH' - characters starting at index 1 and extending up to but not including index 4.

str[1:3]

• str[1:5] is 'YT' - characters starting at index 1 and extending up to but not including index 3.

str[1:2]

• str[1:5] is 'Y' - characters starting at index 1 and extending up to but not including index 2.

str[:-1]

• str[:-1] is 'PYTHO' - omitting either index defaults to the start or end of the string.

str[:]

• str[:] is 'PYTHON' - omitting both always give us the copy of whole string.