how to write hex formatted string into a binary file

[Ramees219]

hi everyone i need help .
i have a function that return a sequence of strings ex:-

[5]2A3D35E89C65379362FF
[0]AA549860FDEED365895634
[9]4512EE67AD9860
[2]528465362698AEFF56
[]85FFE6A3C9524632

SO you can see each string start with bracket [] in side a one digit value or empty bracket then nicely arranged string hex values . so i need this string value converted into hex and stored into a binary file and i need to read them back as it is how can i do this . i goggled it but i didn't under stand .. so i all kind of help appreciated