Data structure

1.

Data structure:
String. Indexing
and slicing

2.

Learning objectives:
• 11.2.2.3 apply functions and string processing
methods;
• 11.2.2.1 perform access to the elements of strings,
lists, tuples;
• 11.2.2.2 use slicers to process the string;
• 11.2.3.6 determine the difference between different
data structures.

3.

A string is a sequence of characters.
Strings are enclosed in quotes:
"Hello, World!"
'Python is fun!’
Strings are used to store and manipulate text in
Python.
fixed_word = 'Programming'
print(fixed_word)

4.

Indexing allows us to access individual characters in a
string.
Positive indexing starts from 0:
Example: "Python"
P = index 0
y = index 1
n = index 3
Negative indexing starts from -1 (last character):
Example: "Python"
n = index -1
P = index -6

5.

Slicing is used to extract parts of a string.
Syntax: string[start:end:step]
start: Starting index (inclusive)
end: Ending index (exclusive)
step: Interval between characters (optional)

6.

Given: word = "Python"
1.word[0:2] → "Py"
2.word[2:5] → "tho"
3.word[::2] → "Pto" (every second character)
4.word[::-1] → "nohtyP" (reverses the string)

7.

Task 1: Complete the Table
String
Index/Slice
"Python"
word[0]
"Programming"
word[3:6]
Task 2: Decode the Message
message = "s!gnirtS ekil I“
print (message[::-1])
Output