A binary file consists of a sequence of eight-bit bytes that are sequentially arranged in a binary format. There are two types of binary files: encrypted and text files. However, binary file types span over a broad spectrum of categories like executables, graphics, libraries, databases, archives, etc.
Binary files are not human-readable, and in order to interpret their content, a special program or processor must know in advance how this content is formatted and how to read it.
Let's go through the following examples to discover first how to create a binary file and then how to read its respective content in Julia's ecosystem:
This example shows how to create a binary file while using the command write:
The syntax of this command is as follows:
n = write(filename,x)
This command accepts two parameters:
filename: This represents the path of the binary file to be created.
x: This represents the canonical binary representation of the value to be written.
It returns the number of bytes written.
input = rand(Float32, 2, 2)print("\ninput = ", input)bytes = write("/usercode/output/file.bin", input)print("\nNumber of bytes written = ", bytes)
Let's now dig into the code widget above:
Line 1: We generate a 2-D array of random float values and store the result in the variable input.
Line 2: We print out the content of the variable input.
Line 3: We create a binary file including the content of the variable input.
Line 4: We print out the number of bytes written.
This example shows how to read a binary file while using the command read!:
The syntax of this command is as follows:
read!(filename,x)
This command accepts two parameters:
filename: This represents the path of the binary file to be read.
x: This represents the array hosting the read binary data.
input = rand(Float32, 2, 2)print("\ninput = ", input)write("/usercode/output/file.bin", input)output = Array{Float32}(undef, (2, 2))open("/usercode/output/file.bin") do ioread!(io, output)endprint("\noutput = ",output)print("\nAssert input == output:",input == output)
Let's walk through the code widget above:
Line 5: We initialize a variable called output to an empty 2-D array of float values.
Lines 6–8: We open the binary file, read its content, and store the latter in a variable named output.
Line 9: We print out the content of the variable output.
Line 10: We print out a message asserting that input and output variables are equal.
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