JuliaStats/DataFrames.jl — pull request #387 by milktrader (2013-10-31 15:49:07+00:00)
Title: add lone period to nastrings array

Federal Reserve St. Louis has a rich set of databases and for some reason they use a single "." to denote missing data.

Currently:

````julia
DATE VALUE
[1,] 2013-10-14 "."
[2,] 2013-10-15 "2.75"
[3,] 2013-10-16 "2.69"
[4,] 2013-10-17 "2.61"
[5,] 2013-10-18 "2.60"
[6,] 2013-10-21 "2.63"
[7,] 2013-10-22 "2.54"
[8,] 2013-10-23 "2.51"
[9,] 2013-10-24 "2.53"
[10,] 2013-10-25 "2.53"
[11,] 2013-10-28 "2.54"
[12,] 2013-10-29 "2.53"
````

Pull Request result:

````Julia
DATE VALUE
[1,] 2013-10-14 NA
[2,] 2013-10-15 2.75
[3,] 2013-10-16 2.69
[4,] 2013-10-17 2.61
[5,] 2013-10-18 2.6
[6,] 2013-10-21 2.63
[7,] 2013-10-22 2.54
[8,] 2013-10-23 2.51
[9,] 2013-10-24 2.53
[10,] 2013-10-25 2.53
[11,] 2013-10-28 2.54
[12,] 2013-10-29 2.53

````