R: t test over multiple columns using t.test function

Question

I tried to perform independent t-test for many columns of a dataframe. For example, i created a data frame

set seed(333)
a <- rnorm(20, 10, 1)
b <- rno         


        

Answer 1

Use select_if to select only numeric columns then use purrr:map_df to apply t.test against grp. Finally use broom:tidy to get the results in tidy format

library(tidyverse)

res <- test_data %>% 
  select_if(is.numeric) %>%
  map_df(~ broom::tidy(t.test(. ~ grp)), .id = 'var')
res
#> # A tibble: 3 x 11
#>   var   estimate estimate1 estimate2 statistic p.value parameter conf.low
#>                                  
#> 1 a       -0.259      9.78      10.0    -0.587   0.565      16.2    -1.19
#> 2 b        0.154     15.0       14.8     0.169   0.868      15.4    -1.78
#> 3 c       -0.359     20.4       20.7    -0.287   0.778      16.5    -3.00
#> # ... with 3 more variables: conf.high , method ,
#> #   alternative 

^{Created on 2019-03-15 by the reprex package (v0.2.1.9000)}