In many programming languages, data comes in different forms. If you want to get a yes/no answer to something, there’s a way to represent that: a true/false boolean (often 1 for true, and 0 for false). If you want to represent, say, a street address, that’s a string, because it’s just a big ol blob of undifferentiated text to the computer.
The joke is about how you ask someone a yes or no question, but they respond with something which is not either of those options.
ELI5?
In many programming languages, data comes in different forms. If you want to get a yes/no answer to something, there’s a way to represent that: a true/false boolean (often 1 for true, and 0 for false). If you want to represent, say, a street address, that’s a string, because it’s just a big ol blob of undifferentiated text to the computer.
The joke is about how you ask someone a yes or no question, but they respond with something which is not either of those options.