Detailed explanation of the usage of ifelse, which, and %in% in R language

ifelse, which, %in% are extremely important functions in R language and will often be seen in other programs in the future.

ifelse

ifelse is the abbreviation of if condition judgment statement, its usage is as follows:

ifelse(test,yes,no)

parameter	describe
test	A logical expression that can be judged
yes	The object returned after being judged as true
no	The object returned after being judged as flase

For example:

x = 5
ifelse(x,1,0)

If x is not equal to 0, it returns 1, and if it is equal to 0, it returns 0.

which

which returns a handle with the condition true, and returns its index to the correct logical object.

which(test，=FALSE)

test must be a logical object, a logical array.

For example:

which(LETTERS == "R")

%in%

%in% determines whether the previous object is in the subsequent container

element %in% list veator

1 %in% c(1:3)

Supplementary: R language: if-else condition judgment and any, all, usage method

Basic structure display:

if (7<10) {
  print("Seven is less than ten")
} else{
  print("seven is more than ten")
}

Example demonstration:

Titanic=("/4Gqsnz")  #Read data from the network

1. any()

#any means that as long as any value meets it, it is TRUEif (any(titanicC$Age&gt;70)) {                                              
  print("there are passengers older than 70")
} else{
  print("no one is older than 70")
}

2. all()

#It is true if everything is satisfiedif (all(titanicC$Age&gt;10)) {
  print("all passengers older than 10")
} else{
  print("there are passengers younger than 10")
}

3. ()

#The position of the placement determines whether to delete the missing value of a single variable or delete any missing value of a variableif (any((titanic$Age==100))) {
  print("there are passengers aged 100")
} else{
  print("there are no passengers aged 100")
}                                                                                 
#Any missing records in the database are deletedif (any(titanic$Age==80, =TRUE)) {
  print("there are passengers aged 80")
} else{
  print("there are no passengers aged 80")
}       
#Age This variable has missing records deleted, and other variables can be retained.

4. else if write more repetitive statements

x=100
y=10
if(x<y){
  print("AA")
} else if(x==y){
  print(BB)
} else{
  print(CC)
}

The above is personal experience. I hope you can give you a reference and I hope you can support me more. If there are any mistakes or no complete considerations, I would like to give you advice.