added shebang, replaced if-elses with shortcut notation, ported online mean and variance calc to mean.awk

1 files changed, 6 insertions, 16 deletions

diff --git a/mean_avg.awk b/mean_avg.awk
index 9864dae..945ed3c 100644
--- a/mean_avg.awk
+++ b/mean_avg.awk
@@ -1,4 +1,4 @@
-#!/usr/bin/awk
+#!/usr/bin/awk -f
 
 ### mean_avg.awk
 # average columns of numerical data
@@ -20,7 +20,7 @@ NR == 1 {
 }
 
 # Welford's 'online' algorithm for variance
-NF != 0 {
+NF > 0 {
     if (NF > max_nf)
         max_nf = NF
     for (n=1; n <= NF; n++) {
@@ -30,28 +30,18 @@ NF != 0 {
             mean[n] = mean[n] + delta0[n]/count[n]
             delta1[n] = $n - mean[n]
             M2[n] = M2[n] + delta0[n]*delta1[n]
-            if (count[n] > 1)
-                var[n] = M2[n]/(count[n] - 1)
-            else
-                var[n] = "0"
+            (count[n] > 1) ? var[n] = M2[n]/(count[n] - 1) : var[n] = "0"
         }
     }
 }
 
 END {
-    printf("\n")
-    printf("%s, \t%s,  %s,  %s,  %s\n", "col", "mean", "std_dev", "std_err", "count")
+    print "col", "mean", "std_dev", "std_err", "count"
     for (n=1; n<=max_nf; n++) {
         if (header[n])
-            printf("%s, \t", header[n])
+            print header[n], mean[n], sqrt(var[n]), sqrt(var[n]/count[n]), count[n]
         else
-            printf("col_%g, \t", n)
-        if (count[n]) {
-            printf("%g,  ±%g,  ±%g,  %g\n",
-                mean[n], sqrt(var[n]), sqrt(var[n]/count[n]), count[n])
-        }
-        else
-            printf(",,,,\n")
+            print "col_" n, mean[n], sqrt(var[n]), sqrt(var[n]/count[n]), count[n]
     }
 }