Added the small utility function hms2seconds()

Converts character strings of hours, minutes, seconds to seconds (as numeric).

SubstrateHistory.R

@@ -27,7 +27,7 @@ SubstrateHistory <- function(sampleid) {
    empty.names <- names(sample.history)[which(empty.cols)]
    # Remove the identified empty columns plus those columns deemed unwanted
    sample.history <- sample.history[, -c(which(empty.cols == TRUE), 
-                                         which(names(sample.history) == "sampleid"), 
+                                         #which(names(sample.history) == "sampleid"), 
                                          which(names(sample.history) == "created"), 
                                          which(names(sample.history) == "project"))]
    # Save the empty column names as attribute to sample.history dataframe

hms2seconds.R

@@ -0,0 +1,28 @@
+##################################################
+################# hms2seconds ####################
+##################################################
+hms2seconds <- function(hms_vec) {
+   ## Description:
+   ##   Converts an hh:mm:ss time into seconds.
+   ## Usage:
+   ##   hms2seconds(hh:mm:ss)
+   ## Arguments:
+   ##     hms_vec: a character vector
+   ## Value:
+   ##   A numeric vector with the same number of elements
+   ##   as the input vector
+   #
+   seconds <- rep(NA, length(hms_vec))
+   for (i in 1:length(hms_vec)) {
+      hms_str <- strsplit(hms_vec[i], ":")[[1]]
+      # We assume hours:min:sec, anything else, throw an error
+      if (length(hms_str) != 3) {
+         error("Input must be formatted as hh:mm:ss")
+      }
+      seconds[i] <- 
+         as.numeric(hms_str[1]) * 3600 + 
+         as.numeric(hms_str[2]) * 60 + 
+         as.numeric(hms_str[3])
+   }
+   return(seconds)
+}