NAs introduced by coercion warning, and results of if block not printing - r

Question

When I try to run only one if statement,for ex. if(outcome=="heart attack") I get a warning message : NAs introduced by coercion followed by the correct output. However , when I try to run the entire code listed below I get the warning message but not the output. So why is this happening? I have checked the code several times and don't see any mistakes.
setwd("C:/users/abhinav/Downloads/rprog_data_specdata")
best <- function(state,outcome){
x <- read.csv("outcome-of-care-measures.csv",header=TRUE,stringsAsFactors = FALSE)
g<- vector()
g<- unique(x$State)
h<- c("heart attack","heart failure","pneumonia")
if(any(g==state)==FALSE){
stop("invalid state")
}
if(any(h==outcome)==FALSE){
stop("invalid outcome")
}
if(outcome=="heart attack"){
x <- read.csv("outcome-of-care-measures.csv",stringsAsFactors = FALSE)
y<- as.numeric(x[which(x$State== state),11])
z<-min(y,na.rm=TRUE)
a<- x[which(x[[11]]==z),2]
b<-sort(a)
b[1]
}
if(outcome=="heart failure"){
x <- read.csv("outcome-of-care-measures.csv",stringsAsFactors = FALSE)
y<- as.numeric(x[which(x$State== state),17])
z<-min(y,na.rm=TRUE)
a<- x[which(x[[17]]==z),2]
b<-sort(a)
b[1]
}
if(outcome=="pneumonia"){
x <- read.csv("outcome-of-care-measures.csv",stringsAsFactors = FALSE)
y<- as.numeric(x[which(x$State== state),23])
z<-min(y,na.rm=TRUE)
a<- x[which(x[[23]]==z),2]
b<-sort(a)
b[1]
}
}

Answer 1

The warning comes from trying to coerce character vectors that don't contain numbers to numeric. You can reproduce it with, e.g.,
as.numeric("abc")
Your code is assigning values but not printing them. Try changing b[1] to print(b[1]). Also, read
Why do R objects not print in a function or a "for" loop?
(What's true for for loops is true for if blocks too.)
There are some pretty awful violations of the Don't Repeat Yourself rule here. For example, the dataset is always read in twice, for no reason. And the sort is called in the same way in every if block. Try refactoring the code so that each if block is a call to a function.