CODEWITHSUNDEEP
rrandom
jay.sf
jay.sf

Reputation: 72984

Creating list of randomized data-frames with increasing number in names

I want to create 10 (at work: 50,000) random data-frames with setting seed for sake of reproducibility. The seed should be different for each data-frame, also its name should increase from df_01, df_02 ... to df_10. With help of @akrun 's answer I coded a loop like this:

# Number of data-frames to be created
n <- 10

# setting a seed vector
x <- 42

# loop
for (i in 1:10) {
        set.seed(x)
        a <- rnorm(10,.9,.05)
        b <- sample(8:200,10,replace=TRUE)
        c <- rnorm(10,80,30)
        lst <- replicate(i, data.frame(a,b,c), simplify=FALSE)
        x <- x+i
}

# name data-frames
names(lst) <- paste0('df', 1:10)

Now I have my data-frames, but it seems I can't get he random generation running. All data are similar. When I replace the lst-line with following code at least the seeded randomization works:

print(data.frame(a,b,c))

A crackajack extra would be a hint for leading zeros in the dfs-names in order to sort them.

Any help appreciated, thx!

Upvotes: 3

Views: 217

Answers (1)

ikop
ikop

Reputation: 1790

You get the same results in all your list elements, because you create your list from scratch in every iteration using replicate and replace the previously created one. If you are using a for loop, you do not need replicate.

For the sake of reproducability I would create a vector of seeds before the loop and then set the seed in each iteration. The leading zeros can be produced using sprintf:

## Number of random data frames to create:
n <- 10

## Sample vector of seeds:
initSeed <- 1234
set.seed(initSeed)
seedVec <- sample.int(n = 1e8, size = n, replace = FALSE)

## loop:
lst <- lapply(1:n, function(i){
            set.seed(seedVec[i])
            a <- rnorm(10,.9,.05)
            b <- sample(8:200,10,replace=TRUE)
            c <- rnorm(10,80,30)
            data.frame(a,b,c)
        })
## Set names with leading zeroes (2 digits). If you want
## three digits, change "%02d" to "%03d" etc.
names(lst) <- paste0('df', sprintf("%02d", 1:10))

Upvotes: 1

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