> 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/julia/strings-and-characters.md).

# Strings and Characters

This page provides syntax for strings and characters in Julia as well as some of their associated functions. Each section includes an example to demonstrate the described syntax or function.

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

* `Char` is a single character
* `String` is a sequence of one or more characters (index values start at `1`)

### Some functions 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                                 | `length(word)`                     |
| extract `nth` character from `word`               | `word[n]`                          |
| extract substring `nth-mth` character from `word` | `word[n:m]`                        |
| search for `letter` in `word`                     | `findfirst(isequal(letter), word)` |
| search for `subword` in `word`                    | `occursin(word, subword)`          |
| remove record separator from `word` (e.g., `n`)   | `chomp(word)`                      |
| remove last character from `word`                 | `chop(word)`                       |

Use `typeof()` function to determine type

Input:

```julia
# chars_and_strings.jl

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

word_length = length(word)
word_first_char = word[1]
word_subword = word[6:8]

println("Length of word: $word_length")
println("First character: $word_first_char")
println("Last three characters: $word_subword")

println("$letter is in $word: $(findfirst(isequal(letter), word))")
println("$subword is in $word: $(occursin(subword, word))")
println("chop off the last character: $(chop(word))")
```

Output:

```julia
Length of word: 8
First character: g
Last three characters: bye
b is in good-bye: 6
good is in good-bye: true
chop off the last character: good-by
```

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

* Julia Documentation: [Manual - Strings](https://docs.julialang.org/en/v1/manual/strings/)
* Julia Documentation: [Base - Strings](https://docs.julialang.org/en/v1/base/strings/)
* Think Julia: [Chapter 8 - Strings](https://benlauwens.github.io/ThinkJulia.jl/latest/book.html#chap08)


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