# Simulation Framework with Logging to Tabular Data

**URL:** <https://discourse.julialang.org/t/simulation-framework-with-logging-to-tabular-data/5205>\
**Category:** General Usage\
**Tags:** question\
**Created:** [August 3, 2017, 4:07pm UTC](https://discourse.julialang.org/t/simulation-framework-with-logging-to-tabular-data/5205 "2017-08-03T16:07:07Z")\
**Posts on this page:** 1\
**Showing post:** 21

<div class="post-metadata">

**Author:** ![philip](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/philip/32/17191_2.png) [@philip](https://discourse.julialang.org/u/philip)\
**Post date:** [February 12, 2018, 5:59pm UTC](https://discourse.julialang.org/t/simulation-framework-with-logging-to-tabular-data/5205/21 "2018-02-12T17:59:29Z")

</div>

I think this [technique](https://discourse.julialang.org/t/get-fieldnames-and-values-of-struct-as-namedtuple/8991/3) is interesting. Perhaps if someone can edit the `to_named_tuple` piece this could work:

```julia

using DataFrames, NamedTuples

#gentup(struct_T) = NamedTuple{( fieldnames(struct_T)...,),
# Tuple{(fieldtype(struct_T,i) for i=1:fieldcount(struct_T))...}}
#
#@generated function to_named_tuple_generated(x)
# nt = Expr(:quote, gentup(x))
# tup = Expr(:tuple)
# for i=1:fieldcount(x)
# push!(tup.args, :(getfield(x, $i)) )
# end
# return :($nt($tup))
#end
#        
#        

#to_named_tuple_naive(p) = (; (v=>getfield(p, v) for v in fieldnames(typeof(p)))...)

        

mutable struct Person
    age::Int64
    id::Int64
    name::String
    weight::Float64
    blood_type::String
    average_resting_heart_rate::Int64
    IQ::Int64
end

function update!(person::Person)
    person.age += 1
    person.weight += rand() - 0.5
end

function logging_df(a_struct)
        DataFrame(prepend!(map(x -> fieldtype(a_struct, x), 
                               fieldnames(a_struct)
                              ),
                           [Int64]
                          ),
                  prepend!(fieldnames(a_struct),
                           [:timestep]
                          ),
                  0)
end
    
p = Person(18, 123, "foo", 72.5, "AB", 66, 100);
    
function log!(simresults, t, p)
        push!(simresults, prepend!(to_named_tuple(p),[t]))
end
    
all_people = [p]
    
function run_simulation!(timesteps::Int64, all_people, simresults)
    for t in 1:timesteps
        map(update!,all_people)
        log!(simresults,t,all_people)
    end
end

simresults = logging_df(Person)
run_simulation!(10,all_people,simresults)
simresults

```

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