Why Clojure?

I think if all you are doing is reading files line by line, reading a database dataset etc, then your choice of language is probably irrelevant. Choose whatever you prefer typing.

But here's CLojres read a file line by line and print it out:

    C:\\foo.txt
    "THis is line 1
     This is line 2
     This is line 3"

     (with-open [rdr (io/reader "C:\\foo.txt")]
        (doall (map println (line-seq rdr))))
      =>THis is line 1
        This is line 2
        This is line 3

A simple function to read a specified file line by line

   (defn read-file-line-by-line [file-path]
      (with-open [rdr (io/reader file-path)]
         (doall (line-seq rdr))))

   (read-file-line-by-line "C:\\foo.txt")
   => ("THis is line 1" "This is line 2" "This is line 3")

To read the line by line and convert them to upper case

     (map clojure.string/upper-case (read-file-line-by-line "C:\\foo.txt"))
     => ("THIS IS LINE 1" "THIS IS LINE 2" "THIS IS LINE 3")

Check out Rosetta Code: https://rosettacode.org/wiki/CSV_data_manipulation

It's a wiki, not a blog, but I've lost countless hours browsing through it and trying stuff out for myself.

Not original poster, but my take is:

- Immutable data-structures with concise literals for lists, vectors, maps, and sets. Having pure functions and immutable data-structures makes code easier to reason about, easier to test, and thread-safe.

(But clojure doesn't "force" you to be pure. The idea is that you write as much of your code in pure functions as you can, and push the IO and impure parts to the extremities. It's very pragmatic in this way, and you can get real work done.)

- Simple syntax:

While the syntax may be intimidating at first and arithmetic looks weird to untrained eye, once you realize that everything is a function (or a special form that also looks just like a function), the very light syntax and consistency feels amazing/refreshing.

- Macro system:

This is tied to the previous point. Since all your code is technically a "list", and you have something akin to a pre-processor where you have the full library of clojure functions to manipulate data. But in this pre-processing phase, your data is the code. (the code is a list). Now you can dynamically re-arrange or re-write code. Lookup homoiconicty and learn about the kinds of things you can do in macros that can't be done in other languages.

- Capabilitis for general programming, abstractions, code re-use etc.

- Performance is quite good. It's often nearly as fast as java, yet your codebase might be 10x smaller because the language is so expressive.

- Concise/expressiveness. Clojure comes with a nice built-in library with generic functions that you re-use again and again. Give a programmer a few dozen of these functions and it's amazing what can be composed to solve many problems succinctly and elegantly.

- There are surely other benefits, but the last one I'll leave with is hard to explain unless you have felt it before. It's REPL driven development.

Clojure comes with some seriously awesome REPLs (i.e. a shell for interactive tinkering with the language). Other languages may have some form of REPL, but no other language in my experience has come close to the feel you get in a clojure REPL. I can best explain it as a freedom of very light-weight experimentation that you use to write your code. It's a playground for writing functions with very quick feedback to see if your code will work or not. One factor that makes the clojure repl experience so nice ties back again to the succinctness and expressiveness of the language. Typing commands in the repl is painless because it's concise, not a lot to type, and then the feedback is so instant.

Somehow when I write code in python, java, javascript, or other languages, I just don't use their REPL or shell as often. It's just not quite the same as the clojure repl experience.

This is all nice and exciting until you start to 1) Debug code, the high density of clojure code means that this is really painful. 2) Read code you wrote a while back. The high density of clojure code means that this is really painful.

High density?