#tutorials http://www.scolvin.com/juliabyexample/
http://julialang.org/learning/
http://dataframesjl.readthedocs.org/en/latest/
#init config
show version info versioninfo()
Pkg.status() and Pkg.add() may fails, run Pkg.init("https://github.com/JuliaLang/METADATA.jl"), default value is "git://github.com/JuliaLang/METADATA.jl" that doesn't work
Inside julia shell, type ; will go to external shell, run the following commands, adding packages will succeed. git config --global url."https://".insteadOf git://
Pkg.available() list available packages online
Pkg.status() list installed packages
See more Pkg.installed(), Pkg.update()
using Package: import all functions to the current namespace
import Package: # will enable you to specify which package the function is called from
Package Gadfly or Winston or PyPlot are able to be used to plotting
Package DataFrames are used to operate on tabular data Pkg.add("RDatasets"), have some useful datasets for exercise
mean -- get average median -- get middle item
reshape data(long form to wide form, and the reverse) using "stack" function