R DT data.table Join

2016-10-11. Category & Tags: DT, R, Data.table, Join

This is part of PML notes. ~~HDD: r_data_table_start~~

Prepare Data #

library(dplyr)
library(readr)
library(data.table)
hero = "
name,       alignment, gender,   publisher
Magneto,    bad,       male,     MarvelDuplicate
Storm,      good,      female,   MarvelDuplicate
Batman,     good,      male,     DC
Joker,      bad,       male,     DC
Catwoman,   bad,       female,   DC
Hellboy,    good,      male,     Dark Horse Comics
"
hero = read_csv(hero, trim_ws = TRUE, skip = 1)
hero = data.table(hero)

publisher = "
publisher,   yr_founded
DC,              1934
MarvelDuplicate, 1939
MarvelDuplicate, 8888
Image,           1992
"
publisher = read_csv(publisher, trim_ws = TRUE, skip = 1)
publisher = data.table(publisher)

For all the join commands, if a key is set for both dt, then on = 'key_col_name' can be elided.

...

Notes of Practical Machine Learning (Coursera PML)

2016-06-28. Category & Tags: Practical Machine Learning, PML, R, Notes, Coursera, Johns Hopkins University, Data.table, DT

It has been a long time since I started using R. Recently, I found some old notes, and I prefer to put it in digital archive, this blog post is to achieve the purpose.

DT (data.table) #

data.table cheat sheet

This data.table (DT) instruction is also available on my github, ispiared by
this ref

//TODO #

//TODO: summarize Solve common R problems efficiently with data.table which is must-read. backup
//TODO: summarize High-performance Solution in R
//TODO: check if to summarize Data Analysis in R using data.table
//TODO: Advanced tips and tricks with data.table
//TODO: The official “Getting Started” of DT
//TODO： check tablewrangling.Rmd

...