lines = open(f).read()

The C and Go implementations of uniform random integer include the upper limit, the Python and Rust implementations don't.

And that's just from quickly browsing.

(The implementation of clojure.string/reverse) would only work on Clojure running on JVM. Clojure-clr, ClojureScript or any of the other ones, would use a difference implementation, not using StringBuilder. `(apply str (reverse s))` is then I guess "more" general across Clojure implementations. So Clojure is using StringBuilder, ClojureScript is using regexes + split to list + reverse + rejoin, ClojureCLR I'm not sure, but probably something C# specific.

But in the end, that's all semantics and the point is moot. Since Clojure is a pragmatic language, using an already defined function is obviously better, so no reason why you wouldn't use clojure.string/reverse, all the Clojure implementations have it exposed already.

> Create string t containing the same characters as string s, in reverse order. Original string s must remain unaltered. Each character must be handled correctly regardless its number of bytes in memory.

What encoding? Assuming UTF-8, what is a "character"? A code point? A grapheme? The result of the lack of specification is that the different approaches really solve different problems. Some, like the C implementation, have a naive approach that only solves the problem in fixed size encodings where the width is equal to CHAR_BIT. Others I'm sure run into problems with combining characters

(1) I'm familiar with the language X but I forget e.g. how to "check if a file exists"

(2) I'm learning a new language Y, I know that "checking if a file exists" is a legit need and there must be an idiomatic way to do it in Y, so I look at the entry, alongside implementations in other languages that I'm more familiar with, so I can quickly spot the similitudes and the differences.

I do (1) all the time because my brain has very little onboard memory.

The website is open to contributions without prior validations. This means that not all snippets end up being both correct and idiomatic. I manually revert spam and "obviously incorrect" entries. For languages that I don't know very well, I encourage actual experts to fix snippets, or add a better new implementation, when they see poor contents.