Implement Rename transform

src/TableTransforms.jl

@@ -7,7 +7,7 @@ module TableTransforms
 using Tables
 using ScientificTypes
 using Distributions: Normal
-using Transducers: tcollect
+using Transducers: tcollect, push!!
 using LinearAlgebra
 using Statistics
 
@@ -29,9 +29,10 @@ export
   colapply, colrevert,
 
   # built-in
+  Identity,
   Select,
   Reject,
-  Identity,
+  Rename3,
   Center,
   Scale,
   MinMax,

src/transforms.jl

@@ -213,6 +213,7 @@ end
 
 include("transforms/identity.jl")
 include("transforms/select.jl")
+include("transforms/rename.jl")
 include("transforms/center.jl")
 include("transforms/scale.jl")
 include("transforms/zscore.jl")

src/transforms/rename.jl

@@ -0,0 +1,43 @@
+# ------------------------------------------------------------------
+# Licensed under the MIT License. See LICENSE in the project root.
+# ------------------------------------------------------------------
+
+""" 
+    Rename(Dict(:col₁ => :newcol₁, :col₂ => :newcol₂, ..., :col₁ => :newcolₙ))
+
+Tha transform that renames `col₁` to `newcol₁`, `col₂` to `newcol₂`, ...
+""" 
+struct Rename3 <: Stateless
+    names::Dict{Symbol,Symbol}
+end
+
+function apply(transform::Rename3, table)
+    new_table = (;)
+
+    for col_name in Tables.columnnames(table)
+        col_value = Tables.getcolumn(table, col_name)
+
+        # if the current name is to be changed, retrive the new name
+        #and push a col with it, else push the col with the old name
+        if col_name in keys(transform.names)
+            new_name = transform.names[col_name]
+            new_table = push!!(new_table, new_name => col_value)
+        else
+            new_table = push!!(new_table, col_name => col_value)
+        end
+    end
+
+    𝒯  = table |> Tables.materializer(table)
+    𝒯, nothing
+end
+
+function revert(transform::Rename3, table)
+    # reversing the key-value pairs
+    new_names = Dict()
+    for (new, old) in transform.names
+        new_names[old] = new
+    end
+    # normal apply operation, but on a revered Dict 
+    reversed_transform = Rename3(new_names)
+    apply(reversed_transform, table) |> first
+end