Data update

Task/Display-a-linear-combination/R/display-a-linear-combination.r

@@ -0,0 +1,27 @@
+library(stringr)
+
+basisify <- function(v){
+  terms <- character(0)
+  for(i in seq_along(v)){
+    if(v[i]!=0){
+      terms <- c(terms, str_glue("{v[i]}*e({i})"))
+    }
+  }
+  if(length(terms)==0) return(0)
+  terms <- str_replace_all(terms, fixed("1*"), "")
+  series <- str_flatten(terms, collapse=" + ")
+  return(str_replace_all(series, fixed("+ -"), "- "))
+}
+
+test_vectors <- list(c(1,2,3),
+                     c(0,1,2,3),
+                     c(1,0,3,4),
+                     c(1,2,0),
+                     c(0,0,0),
+                     0,
+                     c(1,1,1),
+                     c(-1,-1,-1),
+                     c(-1,-2,0,-3),
+                     -1)
+
+print(lapply(test_vectors, basisify), quote=FALSE)