Challenge 023 task 1

1 files changed, 64 insertions, 0 deletions

diff --git a/challenge-023/jo-37/perl/ch-1.pl b/challenge-023/jo-37/perl/ch-1.pl
new file mode 100755
index 0000000000..f57add51e9
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+++ b/challenge-023/jo-37/perl/ch-1.pl
@@ -0,0 +1,64 @@
+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0 '!float';
+use PDL;
+use PDL::NiceSlice;
+
+our ($tests, $examples, $order);
+$order //= 1;
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [-order=N] [K...]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+-order=N
+    find forward difference sequence of order N. Default: 1
+    
+K...
+    list of numbers
+
+EOS
+
+
+### Input and Output
+
+say "@{diff($order, @ARGV)}";
+
+
+### Implementation
+
+sub diff {
+    my $n = shift;
+    my $l = pdl @_;
+    $l = $l(1:-1) - $l(0:-2) for 1 .. $n;
+    $l->unpdl;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        is diff(1, [5, 9, 2, 8, 1, 6]),
+            [4, -7, 6, -7, 5], 'example 1';
+        is diff(2, [5, 9, 2, 8, 1, 6]),
+            [-11, 13, -13, 12], 'example 2';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+	}
+
+    done_testing;
+    exit;
+}