Posts Tagged ‘1-line’

Read int from stdin all in just 1 Line (Java 6 or higher)

int n = Integer.parseInt(System.console().readLine());
Note that that under most IDEs System.console will return NULL when the application is invoked via a launcher making it hard to debug.

R: Annotate the panels in a multi-panel lattice plot in 1 line

Just use panel.lmline()

Rails: Add data from seeds to db in 1 Line

rake db:seed

Python: Get the Directory of a Given File in 1 Line



Quick Tip: Run JavaScript Code Block if an Element has been Clicked (in 1 Line)

.click(function(){CODE TO RUN GOES HERE})

Ten 1-line R Hacks to Boost your Productivity

Here are 10 1-line R hacks that will streamline your workflow and increase your productivity.


1. Install problematic packages from source (solves 99% of installation problems)

install.packages(file_name_and_path, repos = NULL, type="source")

The Bash/shell equivalent would be:

 R CMD INSTALL source.library 

2. Count number of unique rows with a condition

 length(unique(df$col[df$col > 0])) 

Rlogo3. Force R not to use scientific notation

options("scipen"=100, "digits"=4)

4. Count number of non-unique, non-NA rows with a condition

sum(data$x<0, na.rm=T)

5. Randomly order rows (useful for drawing a random sample)


6. Conduct pattern matching with wildcards (no REGEX required)

 glob2rx("blue*")[1] "^blue"

7. Add a column of row numbers to a dataframe/object

df$row <- 1:nrow(df)

8. Loop through each unique date and build a subset

uniq <- unique(unlist(data$Date)); for (i in 1:length(uniq)){ data_1 <- subset(data, date == uniq[i]) #your desired function}

9. Drop columns by name <-[, !names( %in% c(“name”, “name1”, “name2”)]

10. Append something to column names

names(df) <-  str_c(nam, '.yourstring’)

Quick Tip: Create Table as Select (CTaS) Hack in MS SQL Server in 1 Line

select * into target_table from [DB]. [dbo].[table]

Quick Tip: Get the Size of MS SQL Server Table in 1 Line

sp_spaceused ‘[dbo].[table]’

Quick Tip: Show Postgres/pSQL Tables in Postgres OR R in 1 Line

Outside of R:


In R:

dt <- dbGetQuery(con1, “SELECT * FROM pg_catalog.pg_tables”)


Quick Tip: How to Connect to a Running Session (shell) in HBase in 1 Line

./bin/hbase shell