Data commit

Task/Statistics-Basic/Nim/statistics-basic.nim

@@ -0,0 +1,32 @@
+import random, sequtils, stats, strutils, strformat
+
+proc drawHistogram(ns: seq[float]) =
+  var h = newSeq[int](11)
+  for n in ns:
+    let pos = (n * 10).toInt
+    inc h[pos]
+
+  const maxWidth = 50
+  let mx = max(h)
+  echo ""
+  for n, count in h:
+    echo n.toFloat / 10, ": ", repeat('+', int(count / mx * maxWidth))
+  echo ""
+
+randomize()
+
+# First part: compute directly from a sequence of values.
+echo "For 100 numbers:"
+let ns = newSeqWith(100, rand(1.0))
+echo &"μ = {ns.mean:.12f}   σ = {ns.standardDeviation:.12f}"
+ns.drawHistogram()
+
+# Second part: compute incrementally using "RunningStat".
+for count in [1_000, 10_000, 100_000, 1_000_000]:
+  echo &"For {count} numbers:"
+  var rs: RunningStat
+  for _ in 1..count:
+    let n = rand(1.0)
+    rs.push(n)
+  echo &"μ = {rs.mean:.12f}   σ = {rs.standardDeviation:.12f}"
+  echo()