add tz for as.POSIXct and simplify code

Author: caijun

R/date_utils.R

@@ -3,31 +3,32 @@ format_timestamp <- function(indf, index = 1) {
     return(indf)
   }
   if (stringr::str_detect(indf[[index]][1], "^\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2} \\+\\d{4}$")) {
-    indf[[index]] <- as.POSIXct(strptime(indf[[index]], format = "%Y-%m-%d %H:%M:%S", tz = "UTC"))
+    indf[[index]] <- strptime(indf[[index]], format = "%Y-%m-%d %H:%M:%S", tz = "UTC")
   }
   else if (stringr::str_detect(indf[[index]][1], "^\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}$")) {
-    indf[[index]] <- as.POSIXct(strptime(indf[[index]], format = "%Y-%m-%d %H:%M:%S", tz = "UTC"))
+    indf[[index]] <- strptime(indf[[index]], format = "%Y-%m-%d %H:%M:%S", tz = "UTC")
   }
   else if (stringr::str_detect(indf[[index]][1], "^\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}$")) {
-    indf[[index]] <- as.POSIXct(strptime(indf[[index]], format = "%Y-%m-%d %H:%M", tz = "UTC"))
+    indf[[index]] <- strptime(indf[[index]], format = "%Y-%m-%d %H:%M", tz = "UTC")
   }
   else if (stringr::str_detect(indf[[index]][1], "^\\d{2}/\\d{2}/\\d{2}$")) {
-    indf[[index]] <- as.POSIXct(strptime(indf[[index]], format = "%m/%d/%y", tz = "UTC"))
+    indf[[index]] <- strptime(indf[[index]], format = "%m/%d/%y", tz = "UTC")
   }
   else if (stringr::str_detect(indf[[index]][1], "^\\d{2}/\\d{2}/\\d{4}$")) {
-    indf[[index]] <- as.POSIXct(strptime(indf[[index]], format = "%m/%d/%Y", tz = "UTC"))
+    indf[[index]] <- strptime(indf[[index]], format = "%m/%d/%Y", tz = "UTC")
   }
   else if (stringr::str_detect(indf[[index]][1], "^\\d{4}\\d{2}\\d{2}$")) {
-    indf[[index]] <- as.POSIXct(strptime(indf[[index]], format = "%Y%m%d", tz = "UTC"))
+    indf[[index]] <- strptime(indf[[index]], format = "%Y%m%d", tz = "UTC")
   }
   else if (stringr::str_detect(indf[[index]][1], "^\\d{4}/\\d{2}/\\d{2}/\\d{2}$")) {
-    indf[[index]] <- as.POSIXct(strptime(indf[[index]], format = "%Y/%m/%d/%H", tz = "UTC"))
+    indf[[index]] <- strptime(indf[[index]], format = "%Y/%m/%d/%H", tz = "UTC")
   }
   else if (stringr::str_detect(indf[[index]][1], "^\\d{10}$")) {
     # Handle Unix seconds in milliseconds
-    indf[[index]] <- as.POSIXct(as.POSIXlt(indf[[index]], origin = "1970-01-01", tz = "UTC"))
+    indf[[index]] <- as.POSIXlt(indf[[index]], origin = "1970-01-01", tz = "UTC")
   }
 
+  indf[[index]] <- as.POSIXct(indf[[index]], tz = "UTC")
   return(indf)
 }