Extracting data

[roskol]

Hi there

so I have a set of data with about five variables or so. I want to extract specific information from this data that meets a certain criteria, for example my headers could be something like "Name" + "Age" + "Date of birth" + "Sex" and maybe "age group" as well and lets say this dataset is called Class1, so usually when we extract rows or columns I'd use the code Class1[1,] if i want to extract the first row of information or Class1[1,2] if i want to extract the 1st row and second column of the information right?

Now what i want to do with my hypothetical class1 data set is I want to extract the information of the person that was born last in each age group perhaps, like i could have had an age group of 18-24, 25-30 etc and now I want to know the name, age , date of birth, sex and age group of the person who's date of birth is the oldest or youngest perhaps, how would I go about doing that? I know i would need to use the min or max function somehow when extracting but i just don't know how to go about it

[FJCC]

I would first find the maximum DateOfBirth within each group.

library(dplyr)
MaxDates <- Class1 %>% group_by(AgeGroup) %>% 
      summarize(MaxDate = max(DateOfBirth))

I would then filter the initial data using the MaxDates result and the function semi_join()

FilteredData <- semi_join(Class1, MaxDates, by = c("DateOfBirth" = "MaxDate"))

Obviously, I could not test that, not having your data.
Notice I changed your column names to not have spaces since spaces in names causes needless trouble.