convert list to incidence matrix
list2im(x, keepCounts = FALSE, emptyValue = 0, verbose = FALSE, ...)list of vectors
boolean indicating whether to return values indicating the number of occurrences of each item.
any single value that should be used for blank entries,
by default zero 0. Use emptyValue=NA to return NA for missing
entries.
boolean indicating whether to print verbose output.
additional arguments are ignored.
numeric matrix whose rownames were vector items of the input list, and whole colnames were list names.
This function converts a list of vectors into an incidence matrix, where
the rows are the vector items and the columns are the list names.
It uses an object from the arules package called
arules::transactions which offers highly efficient methods
for interconverting from list to matrix. The
transactions class is itself an enhanced data matrix,
which stores data using sparse matrix object type from the
Matrix package, but also associates a data.frame to both
the rows and columns of the matrix to offer additional row and column
annotation, as needed.
Performance benchmarks showed high speed of converting a list to a matrix, but also that the resulting matrix was substantially smaller (5-20 times) then comparable methods producing a data matrix.
When argument keepCounts=TRUE, the method of applying counts only
updates entries with multiple instances, which helps make this step
relatively fast.
Other jam list functions:
colors_from_list(),
im2list_dep(),
im2list(),
imSigned2list_dep(),
imSigned2list(),
list2concordance(),
list2imSigned()
L1 <- list(A=c("C","A","B","A"),
D=c("D","E","F","D"),
A123=c(1:8,3,5),
T=LETTERS[7:9]);
# Default behavior is to make items unique
list2im(L1);
#> Warning: removing duplicated items in transactions
#> A D A123 T
#> 1 0 0 1 0
#> 2 0 0 1 0
#> 3 0 0 1 0
#> 4 0 0 1 0
#> 5 0 0 1 0
#> 6 0 0 1 0
#> 7 0 0 1 0
#> 8 0 0 1 0
#> A 1 0 0 0
#> B 1 0 0 0
#> C 1 0 0 0
#> D 0 1 0 0
#> E 0 1 0 0
#> F 0 1 0 0
#> G 0 0 0 1
#> H 0 0 0 1
#> I 0 0 0 1
# Option to report the counts
list2im(L1, keepCounts=TRUE);
#> Warning: removing duplicated items in transactions
#> A D A123 T
#> 1 0 0 1 0
#> 2 0 0 1 0
#> 3 0 0 2 0
#> 4 0 0 1 0
#> 5 0 0 2 0
#> 6 0 0 1 0
#> 7 0 0 1 0
#> 8 0 0 1 0
#> A 2 0 0 0
#> B 1 0 0 0
#> C 1 0 0 0
#> D 0 2 0 0
#> E 0 1 0 0
#> F 0 1 0 0
#> G 0 0 0 1
#> H 0 0 0 1
#> I 0 0 0 1