6 ms·

Oh that is nasty. For anybody who cares: `a == c` coerces `a` into a number . `a` is a hexadecimal string that happens to have only one non-numeric 'digit', an

• hn_throwaway_99 4y ago
  I think it's a lot less nasty than the Python version. At least the JS version only gives you a weird answer if you're comparing a number to a string, while Python will automatically do a weird type conversion even if you're just comparing two "number looking strings" to begin with. Edit: I'm an idiot, thanks for the responses for correcting me, was thinking PHP but had Python on the brain I guess. Original bad edit: I was downvoted pretty hard, but I think I was just unclear. In Python, doing md5("foo") == md5("bar") returns true because Python converts both strings to numbers first because they have an e in them. That is, in my opinion, Python is doing an unnecessary conversion there that JS doesn't do in that case. See https://stackoverflow.com/questions/12598407/why-does-php-convert-a-string-with-the-letter-e-into-a-number https://stackoverflow.com/questions/12598407/why-does-php-co...
  • cochne 4y ago
    Python doesn’t do any automatic type conversion for strings
    • hn_throwaway_99 4y ago
      That's false, and that's the point I was trying to make, albeit unclearly - see https://stackoverflow.com/questions/12598407/why-does-php-convert-a-string-with-the-letter-e-into-a-number https://stackoverflow.com/questions/12598407/why-does-php-co...
      • andreareina 4y ago
        That's about PHP
  • blep_ 4y ago
    ... no? Python's == never does implicit type conversions unless one of the types overrides it to do so (neither str nor int does)
    • kobalsky 4y ago
      There's one small gotcha with Python. >>> 1 == True True
      • blep_ 4y ago
        Yes, but not because of type conversion: Python's booleans are a subclass of int.
  • mjw1007 4y ago
    I think you keep writing "Python" when you intended to write "PHP".
    • hn_throwaway_99 4y ago
      Lol, thanks, I'm an idiot, it was the brain fart that kept going.
• matisseverduyn 4y ago
  Roughly 7 years ago, I started using strict equality comparisons (===) in PHP and JS to avoid issues like this, and doing so has had zero negative impact on my code and obviously a MUCH higher upside. Is there any reason for using sameness (==) merely beyond convenience?
  • hombre_fatal 4y ago
    I can't even remember the last time I worked in a Javascript project where you could find "==" in the codebase. It even got phased out as a convenient "null or undefined" check. Between it being an ancient footgun and the ubiquity of linters, making fun of "==" code ends up just making fun of beginners.
    • isleyaardvark 4y ago
      Thank goodness for nullish coalescing.
    • eyelidlessness 4y ago
      I still use it for null/undefined checks, because it’s almost always what’s intended/expected. I was surprised to find out recently that this is even a remotely controversial take. I do try to use the newer language features like nullish-coalescing and optional chaining to make the check less necessary, but sometimes it makes more sense (clearer code, less unnecessary code execution) to check for null/undefined and return early.
      • hombre_fatal 4y ago
        Even with a linter that can approve of that one use case, the problem with == these days is that it catches everyone off guard, and every developer who sees the code has to do the same "did they mean to use this or-- oh, it's for a null|undefined check" every single time. Just because of that I've created an `isNil = (x) => x is undefined or null` function and banished == from my code. == can lead to what we've jokingly called tollbooth code: code that can make every reader stop and pay a mental toll while they confirm that the writer did intend to write the code that way.