Convert tskit results from arrays to standard R numeric vectors

NEWS.md

@@ -14,6 +14,8 @@
 
 - Deprecated argument `sampling = ` of the functions `slim()` and `msprime()` has now been permanently removed in favour of the `samples =` argument ([#6bfda57](https://github.com/bodkan/slendr/commit/6bfda57)).
 
+- Avoid the unnecessary `array` type of _tskit_ results returned via reticulate. Numeric vectors (columns of data frames with numerical results) obtained in this way are simple R numeric vector ([#c690334](https://github.com/bodkan/slendr/commit/c690334)).
+
 # slendr 0.3.0
 
 -   SLiM 4.0 is now required for running simulations with the `slim()` engine. If you want to run _slendr_ simulations with SLiM (spatial or non-spatial), you will need to upgrade you SLiM installation. SLiM 3.7.1 version is no longer supported as the upcoming new _slendr_ spatial features will depend on SLiM 4.x and maintaining two functionally identical yet syntactically different back ends is not feasible (PR [#104](https://github.com/bodkan/slendr/pull/104)).

R/tree-sequences.R

@@ -1677,7 +1677,7 @@ multiway_stat <- function(ts, stat = c("fst", "divergence"),
     as.data.frame(t(matrix(set)), stringsAsFactors = FALSE)
   }) %>%
     dplyr::as_tibble() %>%
-    dplyr::mutate(stat = values)
+    dplyr::mutate(stat = as.numeric(values))
 
   result
 }
@@ -1794,7 +1794,7 @@ oneway_stat <- function(ts, stat, sample_sets, mode, windows, span_normalise = N
     set_names <- names(sample_sets)
 
   result <- dplyr::tibble(set = set_names)
-  result[[stat]] <- values
+  result[[stat]] <- as.numeric(values)
   result
 }