Hello,
I believe you should follow Jeremiah's sugestion to first read all csv
files into a list and then rbind them.
Something like the following.
file_list <- list.files(pattern = "*.csv")
df_list <- lapply(file_list, read.csv)
result <- do.call(rbind, df_list)
Hope this helps,
Rui Barradas
Em 07-01-2017 06:51, lily li escreveu:
Thanks, Richard. But if the data cannot fill the constructed data frame,
will there be NA values?
On Fri, Jan 6, 2017 at 10:07 PM, Richard M. Heiberger <r...@temple.edu
<mailto:r...@temple.edu>> wrote:
Incrementally increasing the size of an array is not efficient in R.
The recommended technique is to allocate as much space as you will
need, and then fill it.
> system.time({tmp <- 1:5 ; for (i in 1:1000) tmp <- rbind(tmp, 1:5)})
user system elapsed
0.011 0.000 0.011
> dim(tmp)
[1] 1001 5
> system.time({tmp <- matrix(NA, 1001, 5); for (i in 1:1001)
tmp[i,] <- 1:5})
user system elapsed
0.001 0.000 0.001
> dim(tmp)
[1] 1001 5
On Fri, Jan 6, 2017 at 11:46 PM, lily li <chocol...@gmail.com
<mailto:chocol...@gmail.com>> wrote:
> 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
<ruipbarra...@sapo.pt <mailto:ruipbarra...@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.
>>>
>>> [[alternative HTML version deleted]]
>>>
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>>> ng-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
<http://www.R-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
______________________________________________
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