> For the complete documentation index, see [llms.txt](https://docs.bcbi.brown.edu/codiac-for-health/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bcbi.brown.edu/codiac-for-health/computing/python/strings-and-characters.md).

# Strings and Characters

This page provides syntax for different data types in Python as well as some of their associated functions. Each section includes an example to demonstrate the described syntax or function.

## Strings <a href="#characters_and_strings" id="characters_and_strings"></a>

* A string is a sequence of one or more characters (index values start at 0)

### Some functions and index methods that can be performed on strings <a href="#some_functions_that_can_be_performed_on_strings" id="some_functions_that_can_be_performed_on_strings"></a>

| Action                                        | Function                   |
| --------------------------------------------- | -------------------------- |
| get word length                               | `len("abc")`               |
| extract nth character from word               | `"abc"[n]`                 |
| extract substring nth-mth character from word | `"abc"[n:m]`               |
| search for character in word                  | `"abc".index("character")` |
| search for subword in word                    | `"ab" in "abc"`            |
| remove white spaces from the end of a word    | `"abc   ".strip()`         |
| remove last character from word               | `"abc"[:-1]`               |
| determine data structure type                 | `type("abc")`              |

Input:

```python
# strings.py

letter = "b"
word = "good-bye"
subword = "good"

word_length = len(word)
word_first_char = word[0]
word_subword = word[5:8]

print(f"Length of word: {word_length}")
print(f"First letter: {word_first_char}")
print(f"Last three characters: {word_subword}")

print(f"{letter} is in {word}: {(word.index(letter))}")
print(f"{subword} is in {word}: {(subword in word)}")
print(f"remove the last character: {(word[:-1])}")
```

Output:

```python
Length of word: 8
First character: g
Last three characters: bye
b is in good-bye: 5
good is in good-bye: True
chop off the last character: good-by
```

## Resources <a href="#documentation" id="documentation"></a>

* W3 Schools: [Python Strings](https://www.w3schools.com/python/python_strings.asp)


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