# Calculate statistics (Mean/STD) on Temporal Time Series

**URL:** https://discourse.julialang.org/t/calculate-statistics-mean-std-on-temporal-time-series/9047
**Category:** New to Julia
**Created:** [February 14, 2018, 2:31am UTC](https://discourse.julialang.org/t/calculate-statistics-mean-std-on-temporal-time-series/9047 "2018-02-14T02:31:35Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Max-Zara](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/max-zara/32/3393_2.png) [@Max-Zara](https://discourse.julialang.org/u/Max-Zara)
#### Post date: [February 14, 2018, 2:31am UTC](https://discourse.julialang.org/t/calculate-statistics-mean-std-on-temporal-time-series/9047/1 "2018-02-14T02:31:35Z")

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Hi,  
I would like to calculate some basic statistics on a TimeSeries - mean and standard deviation, however I get an error:

std(ts\_data[:RandomWalk])  
ERROR: MethodError: no method matching /(::Tuple{Date,Array{Float64,1}}, ::Int64)

What is the correct way of doing this:

using Temporal, Base.Dates  
date\_array=collect(Dates.today()-Day(365):Day(1):today())  
random\_walk = cumsum(randn(length(date\_array)))+100.00  
ts\_data = TS(random\_walk, date\_array, :RandomWalk)  
std(ts\_data[:RandomWalk])

Thank you for your help!

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<div class="post-metadata">

### Author: ![JeffreySarnoff](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jeffreysarnoff/32/1980_2.png) [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [February 14, 2018, 2:41am UTC](https://discourse.julialang.org/t/calculate-statistics-mean-std-on-temporal-time-series/9047/2 "2018-02-14T02:41:20Z")

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> [@Max-Zara](#):
>
> using Temporal, Base.Dates
> 
> date\_array=collect(Dates.today()-Day(365):Day(1):today())
> 
> random\_walk = cumsum(randn(length(date\_array)))+100.00
> 
> ts\_data = TS(random\_walk, date\_array, :RandomWalk)
> 
> std(ts\_data[:RandomWalk])

replace the last line

```julia
std((ts_data[:RandomWalk]).values)

```

… or submit an issue about this to Temporal.jl on github (or both)

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<div class="post-metadata">

### Author: ![JeffreySarnoff](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jeffreysarnoff/32/1980_2.png) [@JeffreySarnoff](https://discourse.julialang.org/u/JeffreySarnoff)
#### Post date: [February 14, 2018, 2:44am UTC](https://discourse.julialang.org/t/calculate-statistics-mean-std-on-temporal-time-series/9047/3 "2018-02-14T02:44:20Z")

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with all Temporal.jl series, you can take a column `temporal_series[:colname]` and get its values (shorn of the dates) as a vector:

`temporal_series[:colname].values`

and you can get the dates as a vector:

`temporal_series.index`