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@KasperSkytte
Last active September 12, 2023 10:04
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Convert phyloseq object to ampvis2 object
phyloseq_to_ampvis2 <- function(physeq) {
#check object for class
if(!any(class(physeq) %in% "phyloseq"))
stop("physeq object must be of class \"phyloseq\"", call. = FALSE)
#ampvis2 requires taxonomy and abundance table, phyloseq checks for the latter
if(is.null(physeq@tax_table))
stop("No taxonomy found in the phyloseq object and is required for ampvis2", call. = FALSE)
#OTUs must be in rows, not columns
if(phyloseq::taxa_are_rows(physeq))
abund <- as.data.frame(phyloseq::otu_table(physeq)@.Data)
else
abund <- as.data.frame(t(phyloseq::otu_table(physeq)@.Data))
#tax_table is assumed to have OTUs in rows too
tax <- phyloseq::tax_table(physeq)@.Data
#merge by rownames (OTUs)
otutable <- merge(
abund,
tax,
by = 0,
all.x = TRUE,
all.y = FALSE,
sort = FALSE
)
colnames(otutable)[1] <- "OTU"
#extract sample_data (metadata)
if(!is.null(physeq@sam_data)) {
metadata <- data.frame(
phyloseq::sample_data(physeq),
row.names = phyloseq::sample_names(physeq),
stringsAsFactors = FALSE,
check.names = FALSE
)
#check if any columns match exactly with rownames
#if none matched assume row names are sample identifiers
samplesCol <- unlist(lapply(metadata, function(x) {
identical(x, rownames(metadata))}))
if(any(samplesCol)) {
#error if a column matched and it's not the first
if(!samplesCol[[1]])
stop("Sample ID's must be in the first column in the sample metadata, please reorder", call. = FALSE)
} else {
#assume rownames are sample identifiers, merge at the end with name "SampleID"
if(any(colnames(metadata) %in% "SampleID"))
stop("A column in the sample metadata is already named \"SampleID\" but does not seem to contain sample ID's", call. = FALSE)
metadata$SampleID <- rownames(metadata)
#reorder columns so SampleID is the first
metadata <- metadata[, c(which(colnames(metadata) %in% "SampleID"), 1:(ncol(metadata)-1L)), drop = FALSE]
}
} else
metadata <- NULL
#extract phylogenetic tree, assumed to be of class "phylo"
if(!is.null(physeq@phy_tree)) {
tree <- phyloseq::phy_tree(physeq)
} else
tree <- NULL
#extract OTU DNA sequences, assumed to be of class "XStringSet"
if(!is.null(physeq@refseq)) {
#convert XStringSet to DNAbin using a temporary file (easiest)
fastaTempFile <- tempfile(pattern = "ampvis2_", fileext = ".fa")
Biostrings::writeXStringSet(physeq@refseq, filepath = fastaTempFile)
} else
fastaTempFile <- NULL
#load as normally with amp_load
ampvis2::amp_load(
otutable = otutable,
metadata = metadata,
tree = tree,
fasta = fastaTempFile
)
}
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