---
title: "decompressed(using:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/nsdata/decompressed(using:)"
---

# decompressed(using:)

Returns a new data object by decompressing data object’s bytes.

## Declaration

```swift
func decompressed(using algorithm: NSData.CompressionAlgorithm) throws -> Self
```

## Parameters

- `algorithm`: An algorithm used to decompress the data. For a list of available algorithms, see doc://com.apple.foundation/documentation/Foundation/NSData/CompressionAlgorithm.

## Return Value

Return Value An NSData instance that contains the decompressed buffer data.

## Discussion

Discussion Use this method to inflate in-memory data when you need uncompressed bytes. Specify the same algorithm used to compress the data to successfully decompress it. The following example shows how to create a new NSData instance from data compressed with the NSData.CompressionAlgorithm.zlib algorithm: do {     let uncompressedData = try compressedData.decompressed(using: .zlib) } catch {     print ("Decompression error: \(error)") }

## See Also

### Compressing and Decompressing Data

- [compressed(using:)](foundation/nsdata/compressed(using:).md)
- [NSData.CompressionAlgorithm](foundation/nsdata/compressionalgorithm.md)
- [NSCompressionErrorMaximum](foundation/nscompressionerrormaximum-swift.var.md)
- [NSCompressionErrorMinimum](foundation/nscompressionerrorminimum-swift.var.md)
- [NSCompressionFailedError](foundation/nscompressionfailederror-swift.var.md)
- [NSDecompressionFailedError](foundation/nsdecompressionfailederror-swift.var.md)