LongData and a
Partition whose length fit with idAll, this function
makes the Partition fit with idFewNA.resizePartition(xLongData, yPartition)[LongData]: longitudinal data[Partition]: partition of the longitudinal
data (partition that needs to be resized).Partition .LongData and a
Partition whose length fit with idAll, this function
makes the Partition fit with idFewNA by keeping only the
value corresponding to individual present in idFewNA.