为什么当我尝试将参数传递给if函数时R生成错误

Question

here i am giving the code

#my user defined function
my.display<-function(x,display=TRUE,type="hist",prob=TRUE)
{

  if(display=TRUE)
print("1")

  else hist(x)

  if(type=hist) hist(x) elseif(type=density) plot(density(x))
  cat("Please specify type as either hist or density")

  if(prob=TRUE) hist(x,freq=TRUE) else hist(x,freq=TRUE)
  }

the error r shows is when it passes to the if(display=TRUE), I believe the expression is wrong or something. if the display=TRUE argument then it should print 1 else generate a histogram of the vector x.

if(type=hist) also showing error . someone please help.

Answer 1

= acts as assign operator same as <- operator in R

while == is a logical operator.

So you should use if(display == TRUE) . You might also want to add some {} in your if-else structures for readability.

Try this code for second doubt

updated:

my.display<-function(x,display,type,prob=TRUE)
{if(display==TRUE){
    print("1")
  }
  else 
  if(type=="hist") {hist(x)}
  else
    if(type=="density") {plot(density(x))}
  else
  cat("Please specify type as either hist or density")
  if(prob==TRUE){ hist(x,freq=TRUE)}
  else 
    hist(x,freq=TRUE)
}