how to use “for loop” and “write.csv” at the same time?

问题

I have an array. It has lat,lon,time,and value. Time starts from 1 to 300. Here is part of array for time=1.

myarray[,,1]
     lon                        
    lat -124.5  -123.5  -122.5  -121.5  -120.5  -119.5  -118.5
31.5    0   0   0   0   0   0
32.5    0   0   0   0   0   0
33.5    0   0   0   0   0   0
34.5    0   0   0   0   0   0
35.5    0   0   0   0   0   0
36.5    0   0   0   768.1   0   126.2
37.5    0   0   0.2 0   811 212.1
38.5    0   0   3055    0   243.9   243.7
39.5    0   0   1.5 0.1 3   0
40.5    0.1 16.8    4.3 0.5 2.1 0
41.5    0.2 398.6   0.4 1.2 1.6 0
42.5    0   0.1 0.9 0.1 0.7 0

I want to use "write.csv" and "for loop" at the same time to read the data from array for each time step (1 to 300) and store them in individual .csv files which has "i" as index. I used this command but it seems that it doesn't work:

for (i in 1:300)    write.csv(myarray[,,i],"myarray.i.csv")

回答1:

There are multiple ways of going about this:

paste('myarray', i, 'csv', sep = '.')

or:

sprintf('myarray.%d.csv', i)

I prefer the last one.

回答2:

One way is

for (i in 1:300)  {
write.table(myarray[,,i],file=""myarray.i.csv"",append=TRUE,sep=",",col.names=TRUE,row.names=TRUE) 
  }

回答3:

This should work fine:

n = dim(mydata)[3]

for(i in 1:n) {
  #unpack a 3D array
  mat = mydata[,,i]
  form = sprintf('subject_%s.csv', i)
  write.csv(mat, file = form)

}

来源：https://stackoverflow.com/questions/19481488/how-to-use-for-loop-and-write-csv-at-the-same-time