linux - awk函数语法错误？

Question

谁能看出我为什么会这样

awk: cmd. line:8:   function mma(num) {
awk: cmd. line:8:   ^ syntax error
awk: cmd. line:8:   function mma(num) {
awk: cmd. line:8:                     ^ syntax error

来自这个脚本？

echo "0.24 0.21 0.22 1/1282 10953" | awk '{

  min=""
  max=""
  avg=""

  # find min, max, avg
  function mma(num) {
    if(min==""){min=max=$1};
    if($1>max) {max=$1};
    if($1<min) {min=$1};
    total+=$1;
    count+=1;
    avg=total/count;
  }

  mma($1)
  mma($2)
  mma($3)

  print avg, max, min
}'

Answer 1

函数的定义可以出现在 awk 程序规则之间的任何地方。来自POSIX standard :

The awk language also provides user-defined functions. Such functions can be defined as:

function name([parameter, ...]) { statements }

A function can be referred to anywhere in an awk program; in particular, its use can precede its definition. The scope of a function is global. <snip> Function definitions can appear anywhere in the program where a pattern-action pair is allowed.

这意味着一个有效的 awk 程序看起来像:

( pattern1 ) { action1 }
function name([parameter, ...]) { statements }
( pattern2 ) { action2 }
...

在你原来的代码中，你写错了

( pattern ) { function name([paramter, ...]) { statements }
             action }

因此，您的 awk 部分的更正版本为:

awk 'function mma(num) {
        if(min==""){min=max=$1};
        if($1>max) {max=$1};
        if($1<min) {min=$1};
        total+=$1;
        count+=1;
        avg=total/count;
     }
     { min=""; max=""; avg=""
       mma($1); mma($2); mma($3)
       print avg, max, min
     }'

---

更新:从评论来看，使用起来可能更有用

awk '{ avg=($1+$2+$3)/3; min=avg; max=avg;
       min=($1<min) ? $1 : min; max=($1>max) ? $1 : max
       min=($2<min) ? $2 : min; max=($2>max) ? $2 : max
       min=($3<min) ? $3 : min; max=($3>max) ? $3 : max
       print avg,max, min } ' /proc/loadavg

但是，这是有问题的，因为取平均值的平均值非常...

sar 命令也很有趣。