A string is a sequence of characters, and each character occupies a specific position called an index.

Python allows you to access individual characters of a string using their index values enclosed within square brackets ([]).

String indexing always starts from 0, which means:

• The first character has an index of 0.
• The second character has an index of 1.
• The third character has an index of 2, and so on.

Indexing makes it easy to retrieve a single character from a string without affecting the original string.

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Syntax #

string_name[index]

Components #

Component	Description
string_name	The string variable.
[ ]	Square brackets used for indexing.
index	Position of the character (starting from 0).

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Example 1: Accessing the First Character #

main.py

language = "Python"

print(language[0])

Output #

P

Explanation #

• "Python" contains six characters.
• The first character P is at index 0.
• language[0] returns the first character.

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Example 2: Accessing the Second Character #

main.py

language = "Python"

print(language[1])

Output #

y

Explanation #

• Index 1 refers to the second character.
• The character at index 1 is y.

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Example 3: Accessing the Last Character Using Positive Index #

main.py

language = "Python"

print(language[5])

Output #

n

Explanation #

• The characters of "Python" are:

Index	Character
0	P
1	y
2	t
3	h
4	o
5	n

• The last character has index 5.
• Therefore, language[5] returns n.

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Example 4: Accessing Characters from a Sentence #

main.py

message = "Hello World"

print(message[0])
print(message[6])

Output #

H
W

Explanation #

• Indexing counts every character, including spaces.
• H is located at index 0.
• The space occupies index 5.
• Therefore, W is located at index 6.

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Example 5: Storing an Indexed Character #

main.py

word = "Computer"

letter = word[3]

print(letter)

Output #

p

Explanation #

• The character at index 3 is retrieved.
• It is stored in the variable letter.
• Printing letter displays p.

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Example 6: User Input #

main.py

name = input("Enter your name: ")

print(name[0])

Sample Input #

Alice

Output #

A

Explanation #

• The user enters a string.
• name[0] retrieves the first character of the entered string.
• The first letter of "Alice" is A.

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Example 7: Indexing a Numeric String #

main.py

number = "987654"

print(number[2])

Output #

7

Explanation #

• Although the string contains digits, each digit is treated as a character.
• Index 2 refers to the third character.
• The returned character is '7'.

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Example 8: Using an Index in an Expression #

main.py

text = "Programming"

print(text[0] + text[1])

Output #

Pr

Explanation #

• text[0] returns P.
• text[1] returns r.
• The + operator concatenates the two characters.
• The result is "Pr".

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Example 9: Checking the Type of an Indexed Character #

main.py

text = "Python"

character = text[2]

print(character)
print(type(character))

Output #

t
<class 'str'>

Explanation #

• An indexed character is still a string.
• Python does not have a separate char data type.
• A single character is simply a string of length 1.

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Example 10: Accessing Multiple Characters Individually #

main.py

word = "Python"

print(word[0])
print(word[2])
print(word[4])

Output #

P
t
o

Explanation #

• Index 0 returns P.
• Index 2 returns t.
• Index 4 returns o.
• Each indexed access retrieves one character from the string.

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Common Mistakes #

1. Assuming Indexing Starts from 1 #

Incorrect

word = "Python"

print(word[1])

Incorrect Expectation #

P

Actual Output #

y

Reason

Python uses zero-based indexing.
The first character is always at index 0.

Correct

print(word[0])

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2. Accessing an Index That Does Not Exist #

Incorrect

word = "Python"

print(word[10])

Output #

IndexError: string index out of range

Reason

The string contains only six characters with indices 0 to 5.

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3. Using a Floating-Point Index #

Incorrect

word = "Python"

print(word[2.0])

Output #

TypeError: string indices must be integers

Reason

String indices must always be integers.

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4. Using an Empty String #

Incorrect

text = ""

print(text[0])

Output #

IndexError: string index out of range

Reason

An empty string contains no characters, so there is no valid index.

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Best Practices #

• Remember that string indexing starts from 0.
• Verify that an index exists before accessing it.
• Use descriptive variable names for strings.
• Remember that every indexed character is itself a string.
• Use indexing when you need to retrieve a single character from a string.

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Key Points to Remember #

• Strings are sequences of characters.
• Each character has a unique index.
• Python uses zero-based indexing.
• Square brackets ([]) are used for indexing.
• Index 0 always refers to the first character.
• Indexing returns a string of length 1.
• Accessing an invalid index raises an IndexError.