refactor: some simplifications

Modified Sequent Peak Algorithm (mSPA)/SPA.R

@@ -7,24 +7,23 @@ data <- readr::read_delim(
   delim = "\t", col_names = c("inflow", "release", "precip", "evapo", "downstreamFlow")
 )
 
-time <-
-  data.frame(seq(as.Date("1961/1/1"), as.Date("2007/12/31"), "month"))
-month <-
-  data.frame(format(
+time <- seq(as.Date("1961/1/1"), as.Date("2007/12/31"), "month")
+stora <- data.frame(
+  Month = format(
     as.Date(
-      time$seq.as.Date..1961.1.1....as.Date..2007.12.31.....month..,
+      time,
       format = "%Y-%m-%d"
     ),
     "%m"
-  ))
-year <-
-  data.frame(format(
+  ),
+  Year= format(
     as.Date(
-      time$seq.as.Date..1961.1.1....as.Date..2007.12.31.....month..,
+      time,
       format = "%Y-%m-%d"
     ),
     "%Y"
-  ))
+  )
+)
 n <- NROW(na.omit(data))
 Inflow <- data$inflow
 dem <- data$release
@@ -80,10 +79,8 @@ for (i in 2:n + 1) {
   Zt[i - 1] <- S - Kt1[i - 1]
 }
 
-stora <-
-  data.frame(year, month, Zt) #  [ Storage = reservoir capacity - Deficit ]
-names(stora)[1] <- "Year"
-names(stora)[2] <- "Month"
+stora$Zt <- Zt #  [ Storage = reservoir capacity - Deficit ]
+
 ST <- reshape(
   data = stora,
   idvar = "Year",