Course of Raku / Essentials / Positional data types / Exercises / Count and print command-line arguments

Solution: Count and print command-line arguments

In this program, a for loop is a good choice.

Code

for ^@*ARGS -> $n {
    say "{$n + 1}. @*ARGS[$n]";
}

🦋 Find the program in the file count-and-print-arguments.raku.

Output

Run the program and confirm it prints the arguments and line numbers:

$ raku exercises/positionals/count-and-print-arguments.raku one two three four
1. one
2. two
3. three
4. four

Discussion

This program uses a few handy tricks. First, the for loop goes along the range constructed with ^. So, the range starts from 0 and goes up to (but not including) the value of @*ARGS. In this context, it returns the lengths of the array.

As the first element of an array has index 0, and the task demands we count the lines from 1, this simple shift is computed inside a code block in a string: "{$n + 1} ...".

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