I am working with a data set in R called "USArrests." I want to obtain those states whose murder rate is >8, assault rate >170, and rape rate >21.
Murder Assault UrbanPop Rape states
Alabama 13.2 236 58 21.2 Alabama
Alaska 10.0 263 48 44.5 Alaska
Arizona 8.1 294 80 31.0 Arizona
Arkansas 8.8 190 50 19.5 Arkansas
California 9.0 276 91 40.6 California
Florida 15.4 335 80 31.9 Florida
Georgia 17.4 211 60 25.8 Georgia
Illinois 10.4 249 83 24.0 Illinois
Kentucky 9.7 109 52 16.3 Kentucky
Louisiana 15.4 249 66 22.2 Louisiana
Maryland 11.3 300 67 27.8 Maryland
Michigan 12.1 255 74 35.1 Michigan
Mississippi 16.1 259 44 17.1 Mississippi
Missouri 9.0 178 70 28.2 Missouri
Nevada 12.2 252 81 46.0 Nevada
New Mexico 11.4 285 70 32.1 New Mexico
New York 11.1 254 86 26.1 New York
North Carolina 13.0 337 45 16.1 North Carolina
South Carolina 14.4 279 48 22.5 South Carolina
Tennessee 13.2 188 59 26.9 Tennessee
Texas 12.7 201 80 25.5 Texas
Virginia 8.5 156 63 20.7 Virginia
NA NA NA NA NA <NA>
NA.1 NA NA NA NA <NA>
NA.2 NA NA NA NA <NA>
NA.3 NA NA NA NA <NA>
NA.4 NA NA NA NA <NA>
NA.5 NA NA NA NA <NA>
NA.6 NA NA NA NA <NA>
NA.7 NA NA NA NA <NA>
NA.8 NA NA NA NA <NA>
NA.9 NA NA NA NA <NA>
NA.10 NA NA NA NA <NA>
NA.11 NA NA NA NA <NA>
NA.12 NA NA NA NA <NA>
NA.13 NA NA NA NA <NA>
NA.14 NA NA NA NA <NA>
NA.15 NA NA NA NA <NA>
NA.16 NA NA NA NA <NA>
NA.17 NA NA NA NA <NA>
NA.18 NA NA NA NA <NA>
NA.19 NA NA NA NA <NA>
NA.20 NA NA NA NA <NA>
NA.21 NA NA NA NA <NA>
NA.22 NA NA NA NA <NA>
NA.23 NA NA NA NA <NA>
NA.24 NA NA NA NA <NA>
NA.25 NA NA NA NA <NA>
NA.26 NA NA NA NA <NA>
NA.27 NA NA NA NA <NA>
NA.28 NA NA NA NA <NA>
NA.29 NA NA NA NA <NA>
NA.30 NA NA NA NA <NA>
NA.31 NA NA NA NA <NA>
NA.32 NA NA NA NA <NA>
NA.33 NA NA NA NA <NA>
NA.34 NA NA NA NA <NA>
NA.35 NA NA NA NA <NA>
NA.36 NA NA NA NA <NA>
NA.37 NA NA NA NA <NA>
NA.38 NA NA NA NA <NA>
NA.39 NA NA NA NA <NA>
NA.40 NA NA NA NA <NA>
NA.41 NA NA NA NA <NA>
NA.42 NA NA NA NA <NA>
NA.43 NA NA NA NA <NA>
NA.44 NA NA NA NA <NA>
This was my code
USArrests.1=USArrests[c(USArrests$Murder>8, USArrests$Assault>170, USArrests$Rape>21),].
My question is, what is the more effective way to write this code so it does not have the "NA" rows? I know I can use the "&" operator but it only works for two and not three? Thanks
It appears you are concatenating your logical operators instead of evaluating them with the & “and” statement.
conditions <- USArrests$Murder>8 & USArrests$Assault>170 & USArrests$Rape >21
USArrests[conditions,]
notice that conditions is a series of TRUE and FALSEs.
Alternatively, one can use which() to return the index (rows) which will have the exact same result but may be useful to see:
which(conditions)
# [1] 1 2 3 5 9 10 13 18 20 22 25 28 31 32 40 42 43
USArrests[conditions,]
Some packages make subsetting more intuitive, such as the data.table package.
#install.packages("data.table") #uncomment to install
library(data.table)
USArrests_dt <- as.data.table(USArrests)
USArrests_dt[Murder>8 & Assault>170 & Rape > 21]
which is better for very large datasets and has a convenient print setting. It's a little more complex than your regular data.frame which you should master first.