From ddcb1f73423a9b47d9b457cf3b19f622b0aa567f Mon Sep 17 00:00:00 2001
From: wukong <wukong@longaeva>
Date: Sat, 5 Jan 2019 16:33:14 -0800
Subject: added min and max to mean and mean_avg, fixed regex bugs in mean

---
 mean.awk | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

(limited to 'mean.awk')

diff --git a/mean.awk b/mean.awk
index 816208c..b6a794e 100644
--- a/mean.awk
+++ b/mean.awk
@@ -1,36 +1,35 @@
 #!/usr/bin/awk -f
 
 ### mean.awk
-# calculate mean average
+# calculate mean average of serialized numbers
 
 BEGIN {
     OFS = FS
-    sign = "[+-±]?"
+    sign = "[+-]?"
     decimal = "[0-9]+[.]?[0-9]*"
-    fraction = "[.][0-9]*"
+    fraction = "[.][0-9]+"
     exponent = "([Ee]" sign "[0-9]+)?"
     number = "^" sign "(" decimal "|" fraction ")" exponent "$"
 }
 
 # Welford's 'online' algorithm for variance
 NF > 0 {
-    for (m=1; m<=NF; m++) {
-        if (m ~ number) {
+    for (n=1; n<=NF; n++) {
+        if ($n ~ number) {
             count += 1
-            delta0 = $m - mean
-            mean = mean + delta0/count
-            delta1 = $m - mean
-            M2 = M2 + delta0*delta1
-            if (count > 1)
-                var = M2/(count - 1)
-            else
-                var = "nan"
+            (count == 1 || $n < min) ? min = $n : min = min
+            (count == 1 || $n > max) ? max = $n : max = max
+            delta0 = $n - mean
+            mean += delta0/count
+            delta1 = $n - mean
+            M2 += delta0*delta1
+            (count > 1) ? var = M2/(count - 1) : var = "nan"
         }
     }
 }
 
 END {
-    print "mean", "std_err", "std_dev", "count"
-    print mean, sqrt(var/count), sqrt(var), count
+    print "mean", "std_err", "std_dev", "min", "max", "count"
+    print mean, sqrt(var/count), sqrt(var), min, max, count
 }
 
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