Why can't I knit RMarkdown?

Question

This is the code that I have, and for some reason I can't knit it.

## R Chunk to Import non-path specific dataset
```{r}
act2 <- read.csv(file="~/actdata_2.csv")
```

## Task 1
```{r}
attach(act2)
school <- rep(0,length(act2$courses))
school[act2$courses>=4.0]<-"fulltime"
school[act2$courses<4.0]<-"parttime"
act2<-data.frame(cbind(act2,school))
table(act2$school)
```

## Task 2
```{r}
employment_status <- table(act2$strategy,act2$job)
barplot(employment_status,beside=TRUE, col=c("red","blue"), xlab = "Studying Strategy", ylab = "Number of participants", legend = TRUE, args.legend = list(x="topright",bty="n"))
```

## Task 3
```{r}
task3 <- select(filter(act2, act2$major=="yes"), major, sleep)
summary(task3)
```

The problem comes up at Task 3, and the error says, could not find function "select". What can I do to knit it?

Answer 1

Most of the functions you use in this script are base R functions, so you don't need to load a specific package to use them. However, select comes from dplyr, so R doesn't know what the definition of that function is unless you tell it to go look for that function within the package dplyr. There are two ways you can solve this:

1. Use the library call to load the package whose functions you want to use, e.g. put library(dplyr) at the top of your markdown file

2. Specify which package a given function comes from by listing that package name and "::" in front of that function, e.g., the line under "Task 3" would be:

   task3 <- dplyr::select(filter(act2, act2$major=="yes"), major, sleep)