library(dplyr)
## 
## Attaching package: 'dplyr'
## 
## The following object is masked from 'package:stats':
## 
##     filter
## 
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
installed.packages() %>% 
  rownames() %>% 
  sapply(packageDescription, fields = "Author") %>% 
  grepl("Hadley", .) %>% 
  mean() %>% 
  paste0("Your Hadley-index is ", .)
## [1] "Your Hadley-index is 0.172413793103448"