Function stddev() calculates the standard deviation of numbers in an alias. Only one row from the alias will be kept after this function is called, and all the rest rows will be abandoned.

Arguments：

• Number <number>, auto-abstraction: UUID of NODE/EDGE, row index (starting from 0) of PATH/TABLE, or the first element of ARRAY

Returns：

• Stddev value <number>

ATTR (Numeric value)

Example: find the outbound 1-step paths from Card CA001, and calculate the standard deviation value of the amount of money transferred

n({_id == "CA001"}).re({@transfer} as pay).n({@card})
return stddev(pay.amount)