--- title: 4.2 String Indexing description: "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…" url: "https://magenta-tarsier-454184.hostingersite.com/docs/python-programming/strings-python/4-2-string-indexing/" updated: "2026-07-29" category: Python Programming / Strings --- # 4.2 String Indexing 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. --- ## 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). | --- ## 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. --- ## 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`. --- ## 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`. --- ## 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`. --- ## 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`. --- ## 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`. --- ## 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'`. --- ## 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"`. --- ## Example 9: Checking the Type of an Indexed Character **main.py** ``` text = "Python" character = text[2] print(character) print(type(character)) ``` ### Output ``` t ``` ### 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`. --- ## 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. --- # 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]) ``` --- ### 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`. --- ### 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. --- ### 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. --- # 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. --- # 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`.