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>In one case, I was iterating over the contents of what was supposed to be a list, but in some rare circumstances could instead be a string. Instead of throwing

>In one case, I was iterating over the contents of what was supposed to be a list, but in some rare circumstances could instead be a string. Instead of throwing a type error, Python happily went along with it, and iterated over each character in the string individually. I've been using python for about 13 years professionally and I wrote up a list of "things I wish python would fix but I think probably never will" and treating strings as iterable lists of characters was on there. I've seen this bug multiple times and the fix is relatively easy - just to make strings by default non-iterable and use "string.chars" (or something) if you really want to iterate through the chars. Nonetheless, I still love the language and wouldn't use anything else. >Instead of just throwing an error, Python happily went along with it, used an uninitialized value, and then all the logic broke. This one gets caught by linters - unfortunately 90% of most python linters spit out rule violations which aren't important which drowns out stuff like this in the noise.

CydeWeys 7y ago
Iterating over characters in a string is something that's done very often in introductory CS classes, but very little in the real world. Python has support for string finding and regexes; why in the world would I be individually iterating over characters? Generally, when you see that, it's a code smell. So yeah, I totally agree with you, it'd be better if trying to iterate over a string were a flat-out error, and if you really want it, you should mean it. Though Python being dynamic still means that you'll only spot this error at runtime. As for linters, how do they know if your intent was to reassign the value of an existing variable, or to define a new one? The language has no way to indicate which of these is intended.
bakery2k 7y ago
> I wrote up a list of "things I wish python would fix but I think probably never will" What else is on your list? I'd be interested to see what other parts of Python you would wish to change.
- pytester 7y ago
  Among other things: * Implicitly casting strings, integers, dates, etc. to boolean (e.g. "if x" being true if x is a non empty string). Cause of more unexpected bugs that I can count, but would cause massive headaches if implemented and memories of the the 2-to-3 transition would scare anybody away from doing this I think. * Treating booleans as integers (True + True = 2). Probably wouldn't cause that many headaches if implemented but everybody still seems to think it's a neat idea for some reason. * Treating non-package dependencies of pip packages (e.g. C compilers, header files) as something that is either the package's problem or the OS's problem. Nobody looks at this problem and thinks "I should solve this".

CydeWeys 7y ago

Iterating over characters in a string is something that's done very often in introductory CS classes, but very little in the real world. Python has support for string finding and regexes; why in the world would I be individually iterating over characters? Generally, when you see that, it's a code smell. So yeah, I totally agree with you, it'd be better if trying to iterate over a string were a flat-out error, and if you really want it, you should mean it. Though Python being dynamic still means that you'll only spot this error at runtime. As for linters, how do they know if your intent was to reassign the value of an existing variable, or to define a new one? The language has no way to indicate which of these is intended.

bakery2k 7y ago

> I wrote up a list of "things I wish python would fix but I think probably never will" What else is on your list? I'd be interested to see what other parts of Python you would wish to change.

pytester 7y ago
Among other things: * Implicitly casting strings, integers, dates, etc. to boolean (e.g. "if x" being true if x is a non empty string). Cause of more unexpected bugs that I can count, but would cause massive headaches if implemented and memories of the the 2-to-3 transition would scare anybody away from doing this I think. * Treating booleans as integers (True + True = 2). Probably wouldn't cause that many headaches if implemented but everybody still seems to think it's a neat idea for some reason. * Treating non-package dependencies of pip packages (e.g. C compilers, header files) as something that is either the package's problem or the OS's problem. Nobody looks at this problem and thinks "I should solve this".