# joinString

## Category
String

## Arity
**Binary** — `joinString [array, separator]`.

```
joinString <array>   // [array, separator]
```

## Description
Joins an array of strings into a single string, with the separator inserted between each element. Returns the joined string. The right operand is an array: `[stringArray, separator]`.

## How It Works
Calls `string.Join(separator, stringArray)`. Each element in the array is converted to its string representation via `str` if not already a string. The separator is not added before the first element or after the last.

## Usage

### Basic join
```sqf
joinString [["a", "b", "c"], "-"];   // "a-b-c"
joinString [["red", "green"], ", "];  // "red, green"
```

### CSV generation
```sqf
_fields = ["John", "Doe", "42"];
_csv = joinString [_fields, ","];     // "John,Doe,42"
```

### Path building
```sqf
_parts = ["scripts", "ai", "combat.sqf"];
_path = joinString [_parts, "\"];     // "scripts\ai\combat.sqf"
```

### Sentence building
```sqf
_words = ["Hello", "world", "from", "SQF"];
_sentence = joinString [_words, " "];  // "Hello world from SQF"
```

### With numbers (auto-stringified)
```sqf
joinString [[1, 2, 3], ", "];         // "1, 2, 3"
```

### Empty array
```sqf
joinString [[], ","];                  // "" (empty string)
```

### Single element
```sqf
joinString [["only"], ","];            // "only" (no separator added)
```

## Thread Safety
ReadOnly — pure computation, returns new string. Safe from any scheduler.

## See Also
- [splitString](splitString.md) — reverse: split string into array
- [format](format.md) — formatted string output
- [+](add-operator.md) — string concatenation
- [str](str.md) — value to string