Dear R users,

Suppose I have the following data.frame:

myID myType myNum1 myNum2 myNum3
a       Single       10          11           12
b       Single       15          25           35
c       Double      22          33           44
d       Double        4           6             8

and I want to have new records:

myID myType myNum1 myNum2 myNum3
e      Single       12.5       18           23.5
f       Double      13          19.5         28

where record e got its myNum1-3 as the average from record a and b, and
record f got its myNum1-3 as the average from record c and d.

and the final data.frame should be like the following:

myID myType myNum1 myNum2 myNum3
a       Single       10          11           12
b       Single       15          25           35
e       Single       12.5       18           43.5
c       Double      22          33           44
d       Double        4           6             8
f        Double      13          19.5         28

Any idea is appreciated. Thanks beforehand.

Ferry

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