CODEWITHSUNDEEP
rdateif-statementvector
user177196
user177196

Reputation: 728

Conditional statements on comparing elements of three unequal length vectors in R

I am having a pretty interesting problem related to computer's logical thinking in R that I would love to hear your inputs on whether my understanding is correct. Let's say I have 3 vectors A, B, C of date-type strings in the format YYYY-MM-DD (e.g. 2021-01-01, 2021-12-31). Assume length(A) = length(B), but length(C) is at least ten-times larger, and all the elements in each vector A, B and C are in increasing order.

Objective. I need to write an IF() statement to check if any elements chosen from vector A is less than some elements in vector C, and if any element from vector B is greater than some elements in vector C (if Yes, I would do something). Can someone please help shed the light on whether the two IF statements below are equivalent and indeed they helped me achieve this goal?

My attempt.

I initially tried this statement, but it did not quite work due to the unequal length of A, B vs C

if(any(A <= C & C <= B) { 
       do something here
}

After thinking for a while, I somehow think the above statement is equivalent to the following:

if(A <= max(C) & min(C) <= B){ 
      do something here
}

Upvotes: 0

Views: 51

Answers (1)

Allan Cameron
Allan Cameron

Reputation: 173803

An if statement must operate on a length-1 logical test. If you have anything like A <= max(C) then you are operating on a logical vector the same length as A.

If you want to find out if any A is less than any C, and any B is greater than any C you could do:

if(min(A) < max(C) && min(C) < max(B))

Which is of course a length-one logical test.

Upvotes: 1

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