如何在 R 编程中使用 mutate？

Question

The question goes like this. Use mutate to create a dollars_per_day variable, which is defined as gdp/population/365. Create the dollars_per_day variable for African countries for the year 2010. Remove any NA values. Save the mutated dataset as daydollars. My codes are below, is it possible to combine filter and mutate using mutate? Thanks!

#I used this code
library(dplyr) 
library(dslabs) 
data(gapminder) 
daydollars <- mutate(gapminder,continent=="Africa", year=2010, dollars_per_day=gdp/population/365,na.rm = TRUE) 
daydollars

Answer 1

You can use something like this:

 library(dplyr) library(dslabs) data(gapminder) daydollars <- mutate( gapminder, dollars_per_day= ifelse(is.na(gdp), 0, as.numeric(year==1960) * as.numeric(continent=="Africa") * gdp/population/365) ) daydollars

The idea is to apply the filter by multiplying an expression with vectors of True/False.