[R] About populating a dataframe in a loop

[lily li]

Hi Rui,

Thanks for your reply. Yes, when I tried to rbind two dataframes, it works.
However, if there are more than 50, it got stuck for hours. When I tried to
terminate the process and open the csv file separately, it has only one
data frame. What is the problem? Thanks.


On Fri, Jan 6, 2017 at 11:12 AM, Rui Barradas <ruipbarradas at sapo.pt> wrote:

> Hello,
>
> Works with me:
>
> set.seed(6574)
>
> pre.mat = data.frame()
> for(i in 1:10){
>     mat.temp = data.frame(x = rnorm(5), A = sample(LETTERS, 5, TRUE))
>     pre.mat = rbind(pre.mat, mat.temp)
> }
>
> nrow(pre.mat)  # should be 50
>
>
> Can you give us an example that doesn't work?
>
> Rui Barradas
>
>
> Em 06-01-2017 18:00, lily li escreveu:
>
>> Hi R users,
>>
>> I have a question about filling a dataframe in R using a for loop.
>>
>> I created an empty dataframe first and then filled it, using the code:
>> pre.mat = data.frame()
>> for(i in 1:10){
>>      mat.temp = data.frame(some values filled in)
>>      pre.mat = rbind(pre.mat, mat.temp)
>> }
>> However, the resulted dataframe has not all the rows that I desired for.
>> What is the problem and how to solve it? Thanks.
>>
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>>
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>>

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