Tutorial by Examples: t

Basic syntax DT[where, select|update|do, by] syntax is used to work with columns of a data.table. The "where" part is the i argument The "select|update|do" part is the j argument These two arguments are usually passed by position instead of by name. A sequence of steps c...

# example data DT <- data.table(Titanic) Suppose that, for each sex, we want the rows with the highest survival numbers: DT[Survived == "Yes", .SD[ N == max(N) ], by=Sex] # Class Sex Age Survived N # 1: Crew Male Adult Yes 192 # 2: 1st Female Adult Yes...

# example data DT = data.table(iris) DT[, Bin := cut(Sepal.Length, c(4,6,8))] Using .N .N in j stores the number of rows in a subset. When exploring data, .N is handy to... count rows in a group, DT[Species == "setosa", .N] # 50 or count rows in all groups, DT[, .N,...

# example data DT = data.table(iris) DT[, Bin := cut(Sepal.Length, c(4,6,8))] Suppose we want the summary function output for Sepal.Length along with the number of observations: DT[, c( as.list(summary(Sepal.Length)), N = .N ), by=.(Species, Bin)] # Species Bin Min. 1st Q...

To use just the time part of a Date use LocalTime. You can instantiate a LocalTime object in a couple ways LocalTime time = LocalTime.now(); time = LocalTime.MIDNIGHT; time = LocalTime.NOON; time = LocalTime.of(12, 12, 45); LocalTime also has a built in toString method that displays the for...

xml_import_example.info.yml type: module name: XML import example package: Examples description: "This module helps understanding the Batch API and Queue API with an XML import example" core: 8.x xml_import_example.permissions.yml import content from xml: title: 'Import content...

There is no built-in to iterate over enumeration. But there are several ways for enum with only consecutive values: enum E { Begin, E1 = Begin, E2, // .. En, End }; for (E e = E::Begin; e != E::End; ++e) { // Do job with e } C++11 with enum clas...

Just as the random forest algorithm may be applied to regression and classification tasks, it can also be extended to survival analysis. In the example below a survival model is fit and used for prediction, scoring, and performance analysis using the package randomForestSRC from CRAN. require(rand...

survival is the most commonly used package for survival analysis in R. Using the built-in lung dataset we can get started with Survival Analysis by fitting a regression model with the survreg() function, creating a curve with survfit(), and plotting predicted survival curves by calling the predict m...

Go to https://www.arduino.cc/en/Main/Software Click the "Windows Installer" link Follow the instructions

To use the Arduino IDE on Windows without needing to install it: Go to https://www.arduino.cc/en/Main/Software Click the "Windows ZIP file for non admin install" link Extract the archive to a folder Open the folder, and double click Arduino.exe

Open a terminal and run: sudo dnf install arduino Open the Arduino application, or type arduino into the terminal

Open a terminal and run: sudo apt-get install arduino Open the Arduino application, or type arduino into the terminal

:set foldmethod={method} sets the fold method for the current window. This determines how folds are manipulated within that window. Valid options for "method" are: manual (folds are manually created and destroyed by the user) indent (folds are created for lines of equal indentation) m...

zf{motion} creates a fold that covers the text that "motion" would cover. {count}zF creates a fold that covers "count" lines. {range}fo[ld] creates a fold for the lines in the provided range. All three commands are valid only when foldmethod is set to manual or marker. In ...

zo opens a fold underneath the cursor. zO opens all folds underneath the cursor, recursively. zc closes a fold underneath the cursor. zC closes all folds underneath the cursor, recursively. za toggles a fold under the cursor (a closed fold is opened, an opened fold is closed). zM closes all f...

zv will ensure the line containing the cursor is not folded. The minimum number of folds required to expose the cursor line will be opened.

library(RODBC) con <- odbcDriverConnect("driver={Sql Server};server=servername;trusted connection=true") dat <- sqlQuery(con, "select * from table"); close(con) This will connect to a SQL Server instance. For more information on what your connection string should loo...

One really good example of a struct is CGPoint; it's a simple value that represents a 2-dimensional point. It has 2 properties, x and y, and can be written as typedef struct { CGFloat x; CGFloat y; } CGPoint; If you used Objective-C for Mac or iOS app development before, you've almost...

Applying css intuitively doesn't produce the desired results because vertical-align:middle isn't applicable to block-level elements margin-top:auto and margin-bottom:auto used values would compute as zero margin-top:-50% percentage-based margin values are calculated relative to the width of ...