[R] Error in if (class(networks) == "matrix") from a function

[Andrew Simmons]

In general, you should be using inherits(netwotks, "matrix") or
is(networks, "matrix") instead of class() ==

Your function fails because your object has multiple classes so class==
returns multiple logical values so if will fail.

But inherits or is will return one logical value, so if will not raise an
error.

On Wed., Sep. 21, 2022, 15:21 Chao Liu, <psychaoliu using gmail.com> wrote:

> Dear R-Help community,
>
> This is a crosspost on SO but I've had no luck so far. So I have a function
> which computes a centrality index for the nodes in a network or matrix.
> Here is the function:
>
> library(igraph) #load package igraph
> centrality <- function (networks, type = c("indegree", "outdegree",
> "freeman",
>     "betweenness", "flow", "closeness", "eigenvector", "information",
>     "load", "bonpow"), directed = TRUE, lag = 0, rescale = FALSE,
>     center = FALSE, coefname = NULL, ...) {
>     if (is.null(directed) || !is.logical(directed)) {
>         stop("'directed' must be TRUE or FALSE.")
>     }
>     else if (length(directed) != 1) {
>         stop("The 'directed' argument must contain a single logical
> value only.")
>     }
>     else if (directed == FALSE) {
>         gmode <- "graph"
>     }
>     else {
>         gmode <- "digraph"
>     }
>     objects <- checkDataTypes(y = NULL, networks = networks,
>         lag = lag)
>     centlist <- list()
>     for (i in 1:objects$time.steps) {
>         if (type[1] == "indegree") {
>             cent <- degree(objects$networks[[i]], gmode = gmode,
>                 cmode = "indegree", rescale = rescale, ...)
>         }
>         else if (type[1] == "outdegree") {
>             cent <- degree(objects$networks[[i]], gmode = gmode,
>                 cmode = "outdegree", rescale = rescale, ...)
>         }
>         else if (type[1] == "freeman") {
>             cent <- degree(objects$networks[[i]], gmode = gmode,
>                 cmode = "freeman", rescale = rescale, ...)
>         }
>         else if (type[1] == "betweenness") {
>             cent <- betweenness(objects$networks[[i]], gmode = gmode,
>                 rescale = rescale, ...)
>         }
>         else if (type[1] == "flow") {
>             cent <- flowbet(objects$networks[[i]], gmode = gmode,
>                 rescale = rescale, ...)
>         }
>         else if (type[1] == "closeness") {
>             cent <- closeness(objects$networks[[i]], gmode = gmode,
>                 rescale = rescale, ...)
>         }
>         else if (type[1] == "eigenvector") {
>             cent <- evcent(objects$networks[[i]], gmode = gmode,
>                 rescale = rescale, ...)
>         }
>         else if (type[1] == "information") {
>             cent <- infocent(objects$networks[[i]], gmode = gmode,
>                 rescale = rescale, ...)
>         }
>         else if (type[1] == "load") {
>             cent <- loadcent(objects$networks[[i]], gmode = gmode,
>                 rescale = rescale, ...)
>         }
>         else if (type[1] == "bonpow") {
>             cent <- bonpow(objects$networks[[i]], gmode = gmode,
>                 rescale = rescale, tol = 1e-20, ...)
>         }
>         else {
>             stop("'type' argument was not recognized.")
>         }
>         centlist[[i]] <- cent
>     }
>     time <- numeric()
>     y <- numeric()
>     for (i in 1:objects$time.steps) {
>         time <- c(time, rep(i, objects$n[[i]]))
>         if (is.null(centlist[[i]])) {
>             y <- c(y, rep(NA, objects$n[[i]]))
>         }
>         else {
>             if (center == TRUE) {
>                 centlist[[i]] <- centlist[[i]] - mean(centlist[[i]],
>                   na.rm = TRUE)
>             }
>             y <- c(y, centlist[[i]])
>         }
>     }
>     if (is.null(coefname) || !is.character(coefname) || length(coefname) >
>         1) {
>         coeflabel <- ""
>     }
>     else {
>         coeflabel <- paste0(".", coefname)
>     }
>     if (lag == 0) {
>         laglabel <- ""
>     }
>     else {
>         laglabel <- paste0(".lag", paste(lag, collapse = "."))
>     }
>     label <- paste0(type[1], coeflabel, laglabel)
>     dat <- data.frame(y, time = time, node = objects$nodelabels)
>     dat$node <- as.character(dat$node)
>     colnames(dat)[1] <- label
>     attributes(dat)$lag <- lag
>     return(dat)}
>
> Here is the matrix:
>
> dat <- read.table(text="A B #this is edgelist
> 1 2
> 1 3
> 1 2
> 2 1
> 2 3
> 3 1
> 3 2
> 3 1", header=TRUE)
> datmat <- as.matrix(get.adjacency(graph.edgelist(as.matrix(dat),
> directed=TRUE))) #this is the matrix
> colnames(datmat) <- c("1", "2", "3") #rename the columns
>
> When I applied the function to a matrix
> centrality(datmat,type="flow",center=TRUE), it returns the error:
>
> Error in if (class(networks) == "matrix") { :
>   the condition has length > 1
>
> What is the cause of this error? How to fix it? Any help will be greatly
> appreciated!
>
>
> Best,
>
> Chao
>
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>
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