ReadByteArray[src]
gives the contents of src as a ByteArray object.
ReadByteArray[src,n]
reads the first n bytes from src.
ReadByteArray[src,term]
reads until the termination condition term is satisfied.


ReadByteArray
ReadByteArray[src]
gives the contents of src as a ByteArray object.
ReadByteArray[src,n]
reads the first n bytes from src.
ReadByteArray[src,term]
reads until the termination condition term is satisfied.
Details and Options

- In ReadByteArray[src,…], src can be a file given as "filename" or File["filename"], an input-oriented stream such as InputStream or an external process with head ProcessObject.
- ReadByteArray["file",…] and ReadByteArray[File["file"],…] will open "file" for reading if it is not already open. In this case, the file will be closed after reading if the default terminator, EndOfFile, is used.
- The termination condition term can be any of the following:
-
n up to n bytes have been read ByteArray[…] a literal sequence of bytes is encountered EndOfBuffer available content is exhausted EndOfFile the end of the source is reached (default) EndOfLine a byte sequence corresponding to ends of lines {term1,term2,…} any of the termi - If the termination condition consists of a byte sequence, that sequence is simply dropped and is not returned as part of the byte array.
- ReadByteArray[src] or ReadByteArray[src,EndOfFile] reads from the current position until a stream has ended or the external process providing input has terminated.
- If ReadByteArray is called on a source of content that has already been exhausted, it returns EndOfFile.
- ReadByteArray is a blocking function that by default will not return until it has read whatever it is specified to read.
- With the option setting TimeConstraint->t, ReadByteArray waits at most t seconds, then returns whatever it has read by that time.
- ReadByteArray[src,EndOfBuffer] does not block, and returns whatever is already available in the input buffer.
Examples
open all close allBasic Examples (2)
Scope (5)
Read in the file, explicitly specifying the EndOfFile terminator:
Convert the data to expressions:
Read in the first line of text of Alice in Wonderland as an array of bytes:
Read the first 70 bytes of the United States Constitution:
Read until either 70 bytes have been read or an end of line is encountered:
Open a system shell using StartProcess:
Write a command to the process that generates output:
Read the available output as a byte array:
Convert the bytes to a string and notice that it includes the end-of-line character:
Write the command to the process a second time:
This time, read until the end of line is reached:
The byte array no longer encodes an end of line:
Write a request to the socket:
Read until the byte sequence corresponding to GIF89 is read:
Convert the data in the HTTP header to text:
Options (1)
TimeConstraint (1)
Properties & Relations (5)
ReadByteArray[src] is effectively equivalent to ByteArray[BinaryReadList[src]]:
ReadByteArray[src] is effectively equivalent to StringToByteArray[ReadString[src], "ISO8859-1"]:
ReadByteArray[src,n] reads n bytes at once:
BinaryRead[src] reads one byte at a time:
The data is the same as read in by ReadByteArray:
ReadByteArray[src] is effectively equivalent to StringToByteArray[Import[src,"String"],"ISO8859-1"]:
ImportByteArray[ReadByteArray[src]] is effectively equivalent to Import[src]:
History
Text
Wolfram Research (2018), ReadByteArray, Wolfram Language function, https://reference.wolfram.com/language/ref/ReadByteArray.html.
CMS
Wolfram Language. 2018. "ReadByteArray." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ReadByteArray.html.
APA
Wolfram Language. (2018). ReadByteArray. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ReadByteArray.html
BibTeX
@misc{reference.wolfram_2025_readbytearray, author="Wolfram Research", title="{ReadByteArray}", year="2018", howpublished="\url{https://reference.wolfram.com/language/ref/ReadByteArray.html}", note=[Accessed: 14-August-2025]}
BibLaTeX
@online{reference.wolfram_2025_readbytearray, organization={Wolfram Research}, title={ReadByteArray}, year={2018}, url={https://reference.wolfram.com/language/ref/ReadByteArray.html}, note=[Accessed: 14-August-2025]}