Remove duplicated rows...

Aggregate / summarize multiple variables per group (e.g. sum, mean)...

How to reshape data from long to wide format...

How can I remove all duplicates so that NONE are left in a data frame?...

How can I view the source code for a function?...

Replacing NAs with latest non-NA value...

Create binned values of a numeric column...

Extracting specific columns from a data frame...

ggplot with 2 y axes on each side and different scales...

Set default CRAN mirror permanent in R...

What is the difference between require() and library()?...

How should I deal with "package 'xxx' is not available (for R version x.y.z)" warn...

How to sum a variable by group...

What do the %op% operators in mean? For example "%in%"?...

R: what are Slots?...

Paste multiple columns together...

Why are these numbers not equal?...

How to plot all the columns of a data frame in R...

Get filename without extension in R...

Counting the number of elements with the values of x in a vector...

Count number of rows within each group...

How to use the tryCatch() function?...

Counting unique / distinct values by group in a data frame...

How can I save a plot as an image on the disk?...

Count number of rows per group and add result to original data frame...

Remove NA values from a vector...

Multiline Comment Workarounds?...

Order discrete x scale by frequency/value...

Finding ALL duplicate rows, including "elements with smaller subscripts"...

How do you specifically order ggplot2 x axis instead of alphabetical order?...