Strings

Strings are immutable sequences of characters. All string methods return new strings — the original is never modified.

Creating strings

let s = "hello world"
let empty = ""
let escaped = "Line 1\nLine 2"

Supported escape sequences: \", \\, \n, \t, \{, \}.

let s = "hello"
print(s[0])      // "h"
print(s[-1])     // "o"

Each index returns a single-character string (there’s no separate character type).

Insert variable values with {name} inside a string:

let name = "Alice"
let count = 5
print("Hello, {name}! You have {count} items.")

Only variable names are allowed inside {}. For expressions, use a temporary variable:

let total = str(count * 2)
print("Double: {total}")

Or use concatenation:

print("Double: " + str(count * 2))

To include a literal { or } in a string, escape it with \{ and \}:

print("Use \{name\} for interpolation")
// prints: Use {name} for interpolation

Use + to join strings:

let full = "Hello" + ", " + "world!"
print(full)    // "Hello, world!"

Numbers must be converted with str() first:

let msg = "Score: " + str(42)

Method	Returns	Description
`s.len()`	number	Number of characters
`s.contains(sub)`	bool	Whether the string contains `sub`
`s.starts_with(prefix)`	bool	Whether it starts with `prefix`
`s.ends_with(suffix)`	bool	Whether it ends with `suffix`
`s.index_of(sub)`	number or none	Index of first occurrence, or `none`
`s.split(sep)`	array	Split into array of strings on `sep`
`s.replace(old, new)`	string	Replace all occurrences
`s.upper()`	string	Uppercase copy
`s.lower()`	string	Lowercase copy
`s.trim()`	string	Copy with leading/trailing whitespace removed
`s.slice(start, end)`	string	Substring (both args optional)

let input = "Alice,95,A"
let parts = input.split(",")
print(parts[0])    // "Alice"
print(parts[1])    // "95"

let filename = "report.csv"
if filename.ends_with(".csv") {
  print("CSV file detected")
}

let items = ["apple", "banana", "cherry"]
let count = str(items.len())
let list = items.join(", ")
print("Found {count} items: {list}")