# where does this histogram come from?

**URL:** <https://discourse.julialang.org/t/where-does-this-histogram-come-from/20190>\
**Category:** New to Julia\
**Created:** [January 28, 2019, 5:01pm UTC](https://discourse.julialang.org/t/where-does-this-histogram-come-from/20190 "2019-01-28T17:01:18Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Adam\_R](https://avatars.discourse-cdn.com/v4/letter/a/a9a28c/32.png) [@Adam\_R](https://discourse.julialang.org/u/Adam_R)\
**Post date:** [January 28, 2019, 5:01pm UTC](https://discourse.julialang.org/t/where-does-this-histogram-come-from/20190/1 "2019-01-28T17:01:18Z")

</div>

Hey guys, in the below code I call a histogram but I have no idea what library I call it from (plots or pyplot?) or if it’s built in to Julia or what. can anybody provide any insight? I can’t find it in the julia or the plots documentation, in fact in plots I can only find the plot() function.

More broadly, how can I see all of the functionality in a given library? I keep finding myself not knowing how to do something because I can’t find the right method to achieve it.

here’s the code:

using DataFrames  
using CSV  
using Plots  
using PyPlot

df = CSV.read(“data/train.csv”, header = true, delim = “,”)

for column\_name in names(df)[2:end]  
…some unimportant stuff…  
display(histogram(df[column\_name]))  
end

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [January 28, 2019, 5:11pm UTC](https://discourse.julialang.org/t/where-does-this-histogram-come-from/20190/2 "2019-01-28T17:11:33Z")

</div>

```julia
methods(histogram)

```

should display the source locations for all defined methods.

```julia
parentmodule(histogram)

```

will tell you the module it comes from.

> [@Adam\_R](#):
>
> More broadly, how can I see all of the functionality in a given library?

1. `?ModuleName` at the REPL if it is documented (sadly, many modules aren’t),
2. online docs, usually linked from the Github repository (this is usually your best bet for mature packages),
3. `names(ModuleName)` will list the symbols it exports, then you can look at their individual help pages.

---

<div class="post-metadata">

**Author:** ![lazarusA](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lazarusa/32/6571_2.png) [@lazarusA](https://discourse.julialang.org/u/lazarusA)\
**Post date:** [January 28, 2019, 5:18pm UTC](https://discourse.julialang.org/t/where-does-this-histogram-come-from/20190/3 "2019-01-28T17:18:51Z")

</div>

You can look in `StatsBase`, i.e.,

![06%20AM](https://global.discourse-cdn.com/julialang/original/3X/4/4/44f63ed429c9b1f0eafc13dd15a87c706fc28dcb.png)

and call `?fit` for more info.