Rename multiple variables within a pipeline

Question

The pipeline metaphor enabled by packages like dplyr and magrittr is incredibly useful and does great things for making your code readable in R (a daunting task!)

How can one make a pipeline that ended with renaming all the variables in a data frame to a pre-determined list?

Here is what I tried. First, simple sample data to test on:

> library(dplyr)    
> iris %>% head(n=3) %>% select(-Species) %>% t %>% as.data.frame -> test.data
> test.data

               1   2   3
Sepal.Length 5.1 4.9 4.7
Sepal.Width  3.5 3.0 3.2
Petal.Length 1.4 1.4 1.3
Petal.Width  0.2 0.2 0.2

This doesn't work:

> test.data %>% rename(a=1,b=2,c=3)
Error: Arguments to rename must be unquoted variable names. Arguments a, b, c are not.

I wasn't able to figure out the precise meaning of this error from reading the documentation on rename. My other attempt avoids an error by using curly braces to define a code block, but the renaming doesn't actually happen:

> test.data %>% { names(.) <- c('a','b','c')}

Answer 1

'1','2','3'You were correct except use setNames {stats} instead of rename (zx8754 answered in your comment before me)

setNames: This is a convenience function that sets the names on an object and returns the object. It is most useful at the end of a function definition where one is creating the object to be returned and would prefer not to store it under a name just so the names can be assigned.

Your example (Close just change rename with setNames)

iris %>% 
   head(n=3) %>% 
   select(-Species) %>% 
   t %>% 
   as.data.frame %>% 
   rename(a=1,b=2,c=3)

Answer

iris %>% 
   head(n=3) %>% 
   select(-Species) %>%
   t %>%
   as.data.frame %>%
   setNames(c('1','2','3'))

Another Example

name_list <- c('1','2','3')

iris %>% 
   head(n=3) %>% 
   select(-Species) %>%
   t %>%
   as.data.frame %>%
   setNames(name_list)