What’s the difference between the two following sentence?

[vicky21]

Can someone explain what’s the differences?
check<-(check,tm2)
check<-tm2

[GreyMerchant]

Hi,

In this context it is not possible to say. You'll have to define for us what check is and what tm2 is.

[vicky21]

bingo <- LETTERS[1:4]
my <- NULL
check <- NULL
i <- 1
for (i in 1:10) {
  tmp1 <- sample(x = LETTERS, size = 4, replace = F)
  tmp2 <- sum(tmp1 %in% bingo)
  check <- c(check, tmp2)
}

oohhh!sorry!
you mean just like this?

[GreyMerchant]

Hello,

Yes that makes it a lot more clear.

set.seed(1)

bingo <- LETTERS[1:4]
my <- NULL
check <- NULL


for (i in 1:10) {
  tmp1 <- sample(x = LETTERS, size = 4, replace = F)
  tmp2 <- sum(tmp1 %in% bingo)
  check <- c(check, tmp2)
}

tmp1
#> [1] "J" "F" "O" "T"
tmp2
#> [1] 0
check
#>  [1] 2 1 1 0 0 0 1 1 1 0

^{Created on 2020-10-01 by the reprex package (v0.3.0)}

Okay so you will see I have added a set.seed here just so we can understand more what is happening. For this run it seems you want the random output you're getting from sample as it needs to match the letters in bingo.

Essentially what is happening is the following, check needs to be defined as:

check <- c(check, tmp2)

As it gives the loop the ability to keep track of how many letters you matched with. If you only did the below:

check <- tmp2

check will only have stored the last value obtained in tmp2 so as you will see it would have been 0 and not the whole vector of values as printed above.

I hope that answers your question?

[vicky21]

thanks for your explanation!