Converting a binary string representation into binary array in C#

Stumbled across this question on StackOverflow the other day, definitely one for the interview! The question goes:

How do you convert a string such as “01110100011001010111001101110100” to a byte array then used File.WriteAllBytes such that the exact binary string is the binary of the file. In this case it would be the the text “test”.

Here’s my take on the answer :-)

var binaryStr = "01110100011001010111001101110100";

var byteArray = Enumerable.Range(0, int.MaxValue/8)
                          .Select(i => i*8)    // get the starting index of which char segment
                          .TakeWhile(i => i < binaryStr.Length)
                          .Select(i => binaryStr.Substring(i, 8)) // get the binary string segments
                          .Select(s => Convert.ToByte(s, 2)) // convert to byte
                          .ToArray();
File.WriteAllBytes("C:\temp\test.txt", byteArray);


Yan Cui

I’m an AWS Serverless Hero and the author of Production-Ready Serverless. I have run production workload at scale in AWS for nearly 10 years and I have been an architect or principal engineer with a variety of industries ranging from banking, e-commerce, sports streaming to mobile gaming. I currently work as an independent consultant focused on AWS and serverless.

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