数据格式如下
$ cat FILE
Id ht
510 69
510 67
510 65
510 62
510 59
601 29
601 26
601 21
601 20
awk
$ awk '
NR>1{
arr[$1] += $2
count[$1] += 1
}
END{
for (a in arr) {
print "id avg " a " = " arr[a] / count[a]
}
}
' FILE
output
id avg 601 = 24
id avg 510 = 64.4