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ByteArray[{b1,b2,…}]

constructs a ByteArray object containing the byte values bi.

ByteArray["string"]

constructs a ByteArray object by extracting byte values from a Base64-encoded string.

Details
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Scope  
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ByteArray

ByteArray[{b1,b2,…}]

constructs a ByteArray object containing the byte values bi.

ByteArray["string"]

constructs a ByteArray object by extracting byte values from a Base64-encoded string.

Details

  • ByteArray stores data in a memory-efficient way, with the total number of bytes used being close to the length of the array.
  • When displayed in InputForm, a ByteArray object displays as ByteArray["string"], where "string" encodes the bytes in Base64 encoding.
  • In ByteArray[{b1,b2,…}], all the byte values bi should be integers between 0 and 255.
  • ByteArray[{}] and ByteArray[""] produce empty byte arrays. »
  • StringToByteArray[ByteArray[…]] yields a string by interpreting the contents of a byte array using UTF-8 encoding.
  • ExportByteArray[expr,"fmt"] exports an expression via the export format "fmt", giving the result as a byte array. ImportByteArray can be used to convert a byte array to an expression.
  • Normal[ByteArray[…]] yields the list of byte values in the byte array.
  • Functions such as Length and Equal work with ByteArray objects.
  • Functions such as First, Last, Min, and Max yield integer byte values.
  • Part works on ByteArray objects, yielding an integer byte value when it returns a single element, and a ByteArray object when it returns multiple elements.

Examples

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Basic Examples  (2)

Create a ByteArray from a list of byte values:

Wolfram Language code: ByteArray[{1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1}]

Convert back to a list of byte values:

Wolfram Language code: Normal[%]

Create a ByteArray from a Base64-encoded string:

Wolfram Language code: ByteArray["AQIDBAUGBwg="]

Convert to a list of byte values:

Wolfram Language code: Normal[%]

ByteArray uses Base64 in InputForm:

Wolfram Language code: InputForm[ByteArray[%]]

Scope  (6)

Get the length of a ByteArray:

Wolfram Language code: Length[ByteArray[Range[32]]]

Extract parts of a ByteArray:

Wolfram Language code: b = ByteArray[Range[32]]
Wolfram Language code: First[b]
Wolfram Language code: Last[b]

Extract a sequence of bytes:

Wolfram Language code: b[[5 ;; 10]]

Convert to an ordinary array:

Wolfram Language code: Normal[ByteArray["AQIDBAUGBwgJCgsMDQ4PEBESExQVFhcYGRobHB0eHyA="]]

Reverse a byte array:

Wolfram Language code: Reverse@ByteArray[Range[5]]
Wolfram Language code: Normal[%]

Read in a "WXF" file as a ByteArray:

Wolfram Language code: ReadByteArray["ExampleData/atoms.wxf"]

Read it in 30 bytes at a time:

Wolfram Language code: ReadByteArray["ExampleData/atoms.wxf", 30]
Wolfram Language code: ReadByteArray["ExampleData/atoms.wxf", 30]

Close the incrementally read file:

Wolfram Language code: Close["ExampleData/atoms.wxf"]

Export an image as a ByteArray:

Wolfram Language code: ExportByteArray[[image], "PNG"]

Interpret a ByteArray as a PNG image:

Wolfram Language code: ImportByteArray[ByteArray["iVBORw0KGgoAAAANSUhEUgAAADIAAAAwCAYAAABT9ym6AAAAhXpUWHRSYXcgcHJvZmlsZSB0eXBlIGV4aWYAAHja\ VYvBDcMwDAP/mqIjyLJM2uMYiQNkg45fuu0n9yApgbT1vi97felp2dgxABc5csRU6P6juNciDXn+X9MfZGWgoRhTluEkhnJXkqK\ FN+LCAahYcIbnIV8gNQN3o86928QyPusLVffpbh/5eCey7 ... R5YozihqSbGIR7/X0EpFk02b4IBbJZGKOEQBJNrFIIc8ZRQ1JNrFIucQZRQ1JNrFIrcoZRQ1JNs1blFyWqGm\ yhwpM05ROJ+XL7+MDV5zw+GXS/8UqlSJqtzh+13C0W24mGX7vwfoMHwA9xkE/aDGg89BiZJqEDNsQ20OLbQUPLTZ6vtFj6+230I\ Vshgq737AkuT0dqUiSaD58+IP8i1waX/JZRTgD/moxAAAAAElFTkSuQmCC"], "PNG"]

Properties & Relations  (6)

ByteArray uses Base64 encoding of its data in InputForm:

Wolfram Language code: InputForm[ByteArray[{1, 2, 3}]]

This string can be generated using BaseEncode:

Wolfram Language code: BaseEncode[ByteArray[{1, 2, 3}]]

Convert a byte array to an ordinary, one-dimensional list using Normal:

Wolfram Language code: ByteArray[{1, 2, 3}]
Wolfram Language code: Normal[%]

Compute the length of a byte array:

Wolfram Language code: ByteArray[{1, 2, 3}]
Wolfram Language code: Length[%]

Create empty byte arrays:

Wolfram Language code: {ByteArray[{}], ByteArray[""]}

Convert a ByteArray to a string using ByteArrayToString:

Wolfram Language code: ByteArrayToString[ByteArray["YcOhzrE="]]

Convert back to a ByteArray using StringToByteArray:

Wolfram Language code: StringToByteArray["aáα"]

BinarySerialize converts expressions to a sequence of bytes returned as a ByteArray:

Wolfram Language code: BinarySerialize[{1, Plot, "hello", Hold[Now]}]

It can be reversed using BinaryDeserialize:

Wolfram Language code: BinaryDeserialize[ByteArray["ODpmBHMETGlzdEMBcwRQbG90UwVoZWxsb2YBcwRIb2xkcwNOb3c="]]
Wolfram Research (2015), ByteArray, Wolfram Language function, https://reference.wolfram.com/language/ref/ByteArray.html (updated 2023).

Text

Wolfram Research (2015), ByteArray, Wolfram Language function, https://reference.wolfram.com/language/ref/ByteArray.html (updated 2023).

CMS

Wolfram Language. 2015. "ByteArray." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2023. https://reference.wolfram.com/language/ref/ByteArray.html.

APA

Wolfram Language. (2015). ByteArray. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ByteArray.html

BibTeX

@misc{reference.wolfram_2026_bytearray, author="Wolfram Research", title="{ByteArray}", year="2023", howpublished="\url{https://reference.wolfram.com/language/ref/ByteArray.html}", note=[Accessed: 01-September-2026]}

BibLaTeX

@online{reference.wolfram_2026_bytearray, organization={Wolfram Research}, title={ByteArray}, year={2023}, url={https://reference.wolfram.com/language/ref/ByteArray.html}, note=[Accessed: 01-September-2026]}