#sapply

A video tutorial on R programming – The essentials

Here is a my video tutorial on R programming – The essentials. This tutorial is meant for those who would like to learn R,  for R beginners or for those who would like to get a quick start on R. This tutorial  tries to focus on those  main functions that any R programmer is likely to use often rather than trying to cover every aspect of R with all its subtleties. You can clone the R tutorial used…

Fixed R Grouping functions: sapply vs. lapply vs. apply. vs. tapply vs. by vs. aggregate #dev #it #asnwer

R Grouping functions: sapply vs. lapply vs. apply. vs. tapply vs. by vs. aggregate

Whenever I want to do something “map”py in R, I usually try to use a function in the apply family. (Side question: I still haven’t learned plyr or reshape would plyr or reshape replace all of these entirely?)

However, I’ve never quite understood the differences between them [how {sapply, lapply, etc.} apply the…

How to: R Grouping functions: sapply vs. lapply vs. apply. vs. tapply vs. by vs. aggregate

R Grouping functions: sapply vs. lapply vs. apply. vs. tapply vs. by vs. aggregate

Whenever I want to do something “map”py in R, I usually try to use a function in the apply family. (Side question: I still haven’t learned plyr or reshape would plyr or reshape replace all of these entirely?)

However, I’ve never quite understood the differences between them [how {sapply, lapply, etc.} apply the…

Leute!!

Suppose you have a list of 20 dataframes, each of data frame has 10 columns but different rows. You want to know the length of rows in each dataframe without using loop in a single line.

sapply(x,function(y)length(y[[1]]))

where x is a list

If you are after a specific column, just replace the number [[1]] with it.

Cheers