A small tip about R — Subset one column from a dataframe

For example:

temp <- data.frame(x = c(1, 2, 4), y = c(34, 23, 45))

method 1. temp[1] get a data frame

method 2. temp[, 1] get a vector

Below is R code and output.

temp

##   x  y
## 1 1 34
## 2 2 23
## 3 4 45

str(temp)

## 'data.frame':    3 obs. of  2 variables:
##  $ x: num  1 2 4
##  $ y: num  34 23 45

temp[1]

##   x
## 1 1
## 2 2
## 3 4

str(temp[1])

## 'data.frame':    3 obs. of  1 variable:
##  $ x: num  1 2 4

temp[, 1]

## [1] 1 2 4

str(temp[, 1])

##  num [1:3] 1 2 4

Welcome your advice and suggestion!

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