# Yet Another Blog in Statistical Computing

I can calculate the motion of heavenly bodies but not the madness of people. -Isaac Newton

## Test Drive of Julia

```   _       _ _(_)_     |  A fresh approach to technical computing
(_)     | (_) (_)    |  Documentation: http://docs.julialang.org
_ _   _| |_  __ _   |  Type "help()" to list help topics
| | | | | | |/ _` |  |
| | |_| | | | (_| |  |  Version 0.3.0-prerelease+490 (2013-12-15 07:16 UTC)
_/ |\__'_|_|_|\__'_|  |  Commit f8f3190* (0 days old master)
|__/                   |  x86_64-linux-gnu

julia> # load the package

julia> using DataFrames

julia> # read a txt file into dataframe

julia> df1 = readtable("credit_count.txt");

julia> # subset the dataframe

julia> df2 = df1[:(CARDHLDR .== 1), ["DEFAULT", "MAJORDRG", "MINORDRG"]];

julia> # aggregate the data

julia> df3 = by(df2, "DEFAULT", :(MAJOR_DRG = mean(_DF["MAJORDRG"])))
2x2 DataFrame:
DEFAULT MAJOR_DRG
[1,]          0  0.139851
[2,]          1  0.175703

julia> df4 = by(df2, "DEFAULT", :(MINOR_DRG = mean(_DF["MINORDRG"])))
2x2 DataFrame:
DEFAULT MINOR_DRG
[1,]          0  0.213196
[2,]          1  0.292169

julia> # join two dataframes

julia> df5 = join(df3, df4, on = "DEFAULT", kind = :inner)
2x3 DataFrame:
DEFAULT MAJOR_DRG MINOR_DRG
[1,]          0  0.139851  0.213196
[2,]          1  0.175703  0.292169
```

Written by statcompute

December 27, 2013 at 12:26 am

Posted in Big Data, Julia