# AppendFormat

> Interpolates strings into a format string and appends the result to this string.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Collections](/engine/6000.7/script-reference/unity/collections.md)
* **Assembly:** UnityEngine.ManagedKernelModule

## AppendFormat\<T, U, V>(T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0>(this ref T dest, in U format, in T0 arg0) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W>(T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1>(this ref T dest, in U format, in T0 arg0, in T1 arg1) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X>(T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X, Y>(T, T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2, T3>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2, in T3 arg3) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes where T3 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X, Y, Z>(T, T, T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2, T3, T4>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2, in T3 arg3, in T4 arg4) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes where T3 : unmanaged, INativeList<byte>, IUTF8Bytes where T4 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X, Y, Z, \[>(T, T, T, T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2, T3, T4, T5>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2, in T3 arg3, in T4 arg4, in T5 arg5) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes where T3 : unmanaged, INativeList<byte>, IUTF8Bytes where T4 : unmanaged, INativeList<byte>, IUTF8Bytes where T5 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X, Y, Z, \[, \\>(T, T, T, T, T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2, T3, T4, T5, T6>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2, in T3 arg3, in T4 arg4, in T5 arg5, in T6 arg6) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes where T3 : unmanaged, INativeList<byte>, IUTF8Bytes where T4 : unmanaged, INativeList<byte>, IUTF8Bytes where T5 : unmanaged, INativeList<byte>, IUTF8Bytes where T6 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X, Y, Z, \[, \\, ]>(T, T, T, T, T, T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2, T3, T4, T5, T6, T7>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2, in T3 arg3, in T4 arg4, in T5 arg5, in T6 arg6, in T7 arg7) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes where T3 : unmanaged, INativeList<byte>, IUTF8Bytes where T4 : unmanaged, INativeList<byte>, IUTF8Bytes where T5 : unmanaged, INativeList<byte>, IUTF8Bytes where T6 : unmanaged, INativeList<byte>, IUTF8Bytes where T7 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X, Y, Z, \[, \\, ], ^>(T, T, T, T, T, T, T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2, T3, T4, T5, T6, T7, T8>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2, in T3 arg3, in T4 arg4, in T5 arg5, in T6 arg6, in T7 arg7, in T8 arg8) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes where T3 : unmanaged, INativeList<byte>, IUTF8Bytes where T4 : unmanaged, INativeList<byte>, IUTF8Bytes where T5 : unmanaged, INativeList<byte>, IUTF8Bytes where T6 : unmanaged, INativeList<byte>, IUTF8Bytes where T7 : unmanaged, INativeList<byte>, IUTF8Bytes where T8 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.

## AppendFormat\<T, U, V, W, X, Y, Z, \[, \\, ], ^, \_>(T, T, T, T, T, T, T, T, T, T, T, T)

Interpolates strings into a format string and appends the result to this string.

```csharp
public static FormatError AppendFormat<T, U, T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>(this ref T dest, in U format, in T0 arg0, in T1 arg1, in T2 arg2, in T3 arg3, in T4 arg4, in T5 arg5, in T6 arg6, in T7 arg7, in T8 arg8, in T9 arg9) where T : unmanaged, INativeList<byte>, IUTF8Bytes where U : unmanaged, INativeList<byte>, IUTF8Bytes where T0 : unmanaged, INativeList<byte>, IUTF8Bytes where T1 : unmanaged, INativeList<byte>, IUTF8Bytes where T2 : unmanaged, INativeList<byte>, IUTF8Bytes where T3 : unmanaged, INativeList<byte>, IUTF8Bytes where T4 : unmanaged, INativeList<byte>, IUTF8Bytes where T5 : unmanaged, INativeList<byte>, IUTF8Bytes where T6 : unmanaged, INativeList<byte>, IUTF8Bytes where T7 : unmanaged, INativeList<byte>, IUTF8Bytes where T8 : unmanaged, INativeList<byte>, IUTF8Bytes where T9 : unmanaged, INativeList<byte>, IUTF8Bytes
```

### Parameters

**** (T): The string to append to.**** (T): A string to be interpolated and appended.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.**** (T): A FixedString"N"Bytes to interpolate into the format string.

### Returns

| Type                                                                            | Description                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md) | [FormatError.None](/engine/6000.7/script-reference/unity/collections/formaterror/none.md) if successful. Otherwise returns the appropriate [FormatError](/engine/6000.7/script-reference/unity/collections/formaterror.md). |

### Remarks

Similar to `StringBuilder.AppendFormat` but with significant limitations:

* Only supports FixedString"N"Bytes arguments. To use other string types, convert them to FixedString"N"Bytes first.

* Only supports numeric format placeholders of the form `{0}` .. `{N}`.

* No format modifiers ("e.g." `{0:x}`) are supported.

The overloads of this method take up to ten strings to interpolate into the format string.