CODEWITHSUNDEEP
rstringconditional-statements
RonH
RonH

Reputation: 21

R string vector error - the condition has length > 1 and only the first element will be used

I need help with the following R code - my code is: 

best <- function(state, outcome) { 
        ## Read outcome data
        outcome <- read.csv("outcome-of-care-measures.csv", colClasses = "character") enter code here

        ## Check that state and outcome are valid using STOP function and
        ## message "invalid state" or "invalid outcome"

        valid_outcomes <- c("heart attack", "heart failure", "pneumonia")

        if(!state %in% state.abb){
                stop("Invalid state")
        }  
        else if (!outcome %in% valid_outcomes)
        {
                stop("Invalid outcome") 
        }

        return(x)
        ## Return hospital name in that state with lowest 30-day death ## rate
}

It returns: 

Error in best("NY", "health") : Invalid outcome
In addition: Warning message:
In if (!outcome %in% valid_outcomes) { :
   the condition has length > 1 and only the first element will be used

If I use else if (any(!outcome %in% valid_outcomes)) it seems to help, but the logical condition isn't being resolved properly.

Any ideas on how to solve this issue? Thanks

Upvotes: 2

Views: 1088

Answers (2)

Gopala
Gopala

Reputation: 10483

Your if condition is evaluating a vector of output whereas it is designed to take only one logical value. Try this code to see the issue:

> outcome <- c('one', 'two', 'pneumonia')
> valid_outcomes <- c("heart attack", "heart failure", "pneumonia")
> outcome %in% valid_outcomes
[1] FALSE FALSE  TRUE

You see that it returns a vector of true/false values. To put them all into one condition, you can use:

if (!all(outcome %in% valid_outcomes)) { stop('blah') }

Same issue for the states that you need to fix.

Upvotes: 0

Vedda
Vedda

Reputation: 7435

Try this:

 if(!any(state == data$State)) {
    stop('invalid state')
  }

Upvotes: 1

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