Thanks, that was the solution! But in fact I didn't want to have this
"list of lists" layer at all. And now I'm having trouble writing
matrices into the database. It's really really strange... If I write a
matrix into the database manually everything works, but if I create a
function which adds a matrix into the database and then run the function
it fails... Look at this (sorry for the long code block, in fact you can
skip the "sums" and "test_sums" functions):
######################test matrix#######################
m1=matrix(c(
1,0,
0,1
),nrow=2, byrow=TRUE)
#########################sums###########################
sums=function(matrix)
{
c(sort(colSums(matrix)),sort(rowSums(matrix)))
}
######################test_sums#########################
test_sums=function(matrix)
{
liste=database[[nrow(matrix),ncol(matrix)]][[1]]
w=1
if(length(liste)>0){
for(i in 1:length(liste)){
if(all(sums(matrix)==sums(liste[[i]]))){
w0=0
}else{
w0=1}
w=w*w0}
}else{
w=2}
w
}
#####################write to db########################
write_to_db=function(matrix){
en=nrow(matrix)
fn=ncol(matrix)
if(test_sums(matrix)==1){
print("matrix isn't in the DB yet")
database[en,fn][[1]]=list(database[en,fn][[1]], matrix)
}else if(test_sums(matrix)==2){
print("matrix isn't in the DB entry yet and DB is empty")
database[en,fn][[1]][[1]]=list(matrix)
}else{
print("matrix already exists in the DB")
}
}
######################create database##################
database=matrix(list(),2,2)
##trying to write a matrix into db using the function##
write_to_db(m1)
database
###writing a matrix into db without using a function###
en=nrow(m1)
fn=ncol(m1)
if(test_sums(m1)==1){
print("matrix isn't in the DB yet")
database[en,fn][[1]]=list(database[en,fn][[1]], m1)
}else if(test_sums(m1)==2){
print("matrix isn't in the DB entry yet and DB is empty")
database[en,fn][[1]][[1]]=list(m1)
}else{
print("matrix already exists in the DB")
}
database
###########test whether matrix already is in db##########
write_to_db(m1)
And the output is:
[1] "matrix isn't in the DB entry yet and DB is empty"
[,1] [,2]
[1,] NULL NULL
[2,] NULL NULL
[1] "matrix isn't in the DB entry yet and DB is empty"
[,1] [,2]
[1,] NULL NULL
[2,] NULL List,1
[1] "matrix already exists in the DB"
So writing the matrix into the database using the function fails while
writing it using the same commands but not through a function works!
Maybe it's a problem with all these layers in the database matrix?
Petr PIKAL schrieb:
Hi
r-help-boun...@r-project.org napsal dne 19.08.2009 13:04:39:
Strange, it doesn't work for me:
Error in database[4, 4][[1]][1, ] : incorrect number of dimensions
Execution halted
R version 2.9.0 (2009-04-17) on Arch Linux, no additional packages
installed.
database[4,4][[1]][,1]
does not work for me either but it is result of your complicated structure
of nested lists
This works
database[4,4][[1]][[1]][,1]
[1] 0 1 1 1
See the structure
Matrix of lists
database
[,1] [,2] [,3] [,4] [,5]
[1,] NULL NULL NULL NULL NULL
[2,] NULL NULL NULL NULL NULL
[3,] NULL NULL NULL NULL NULL
[4,] NULL NULL NULL List,1 NULL
[5,] NULL NULL NULL NULL NULL
List of lists
database[4,4]
[[1]]
[[1]][[1]]
[,1] [,2] [,3] [,4]
[1,] 0 1 1 1
[2,] 1 0 1 1
[3,] 1 1 0 1
[4,] 1 1 1 0
List which contains your matrix
database[4,4][[1]]
[[1]]
[,1] [,2] [,3] [,4]
[1,] 0 1 1 1
[2,] 1 0 1 1
[3,] 1 1 0 1
[4,] 1 1 1 0
Here is your matrix
database[4,4][[1]][[1]]
[,1] [,2] [,3] [,4]
[1,] 0 1 1 1
[2,] 1 0 1 1
[3,] 1 1 0 1
[4,] 1 1 1 0
Regards
Petr
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