Methods on arrays

When the value elements in an Array{Timestamp} are homogenous, it may be convenient to perform common array computations. The following methods are supported

Method Description
sum sum of the values & span of days
prod product of the values & span of days
mean mean of the values & span of days
var variance of the values & span of days
std standard deviation of the values & span of days
maximum maximum of the values & span of days
minimum minimum of the values & span of days

An example in REPL:

julia> using MarketData

julia> clstamp = Array{Timestamp}(cl)
500-element Array{Timestamps.Timestamp{T},1}:
2000-01-03 | 111.94
2000-01-04 | 102.5
2000-01-05 | 104.0
2000-01-06 | 95.0
2000-01-07 | 99.5
2000-01-10 | 97.75
2000-01-11 | 92.75
⋮
2001-12-20 | 20.67
2001-12-21 | 21.0
2001-12-24 | 21.36
2001-12-26 | 21.49
2001-12-27 | 22.07
2001-12-28 | 22.43
2001-12-31 | 21.9

julia> mean(clstamp)
731 days | 46.190479999999994