Difference between revisions of "File data manipulation"

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== File data manipulation one-liners ==
  
 
* Given a file with a single number on each line, reach only the first 10 lines, sum the total and print each number read.
 
* Given a file with a single number on each line, reach only the first 10 lines, sum the total and print each number read.

Revision as of 21:48, 17 July 2020

File data manipulation one-liners

  • Given a file with a single number on each line, reach only the first 10 lines, sum the total and print each number read.
module read_and_sum;

import std.conv : to;
import std.stdio: writeln;
import std.range : takeExactly, tee;
import std.algorithm.iteration : map, each;

void main()
{
    double total = 0;
    File("./10numbers.txt")
         // lazily iterate by line
        .byLine

         // pick first 10 lines
        .takeExactly(10)
         
         // convert each to double
        .map!(to!double)

         // add element ro total
        .tee!((x) { total += x; })

        // print each number 
        .each!writeln;
}