update codes

ch11.jl

@@ -0,0 +1,85 @@
+# Bogumił Kamiński, 2022
+
+# Codes for chapter 11
+
+# Code for section 11.1
+
+# Code for a note on conversion
+
+x = [1.5]
+x[1] = 1
+x
+
+# Code from section 11.1.1
+
+using Serialization
+walk = deserialize("walk.bin")
+
+Matrix(walk)
+Matrix{Any}(walk)
+Matrix{String}(walk)
+
+plot(walk)
+
+plot(Matrix(walk); labels=["x" "y"] , legend=:topleft)
+
+# Code from section 11.1.2
+
+Tables.columntable(walk)
+
+using BenchmarkTools
+function mysum(table)
+           s = 0 #A
+           for v in table.x #B
+               s += v
+           end
+           return s
+       end
+df = DataFrame(x=1:1_000_000);
+@btime mysum($df)
+
+tab = Tables.columntable(df);
+@btime mysum($tab)
+
+@code_warntype mysum(df)
+
+@code_warntype mysum(tab)
+
+typeof(tab)
+
+function barrier_mysum2(x)
+    s = 0
+    for v in x
+        s += v
+    end
+    return s
+end
+mysum2(table) = barrier_mysum2(table.x)
+@btime mysum2($df)
+
+df = DataFrame(a=[1, 1, 2], b=[1, 1, 2])
+unique(df)
+
+tab = Tables.columntable(df)
+unique(tab)
+
+# Code from section 11.1.3
+
+Tables.rowtable(walk)
+
+nti = Tables.namedtupleiterator(walk)
+for v in nti
+    println(v)
+end
+
+er = eachrow(walk)
+er[1]
+er[end]
+ec = eachcol(walk)
+ec[1]
+ec[end]
+
+identity.(eachcol(walk))
+
+df = DataFrame(x=1:2, b=["a", "b"])
+identity.(eachcol(df))