stackoverflow: initial commit of analysis

.gitignore

@@ -0,0 +1 @@
+stackoverflow

main.go

@@ -0,0 +1,133 @@
+package main
+
+import (
+	"encoding/csv"
+	"fmt"
+	"io"
+	"log"
+	"math"
+	"os"
+	"strings"
+)
+
+func main() {
+	ent := false
+	if len(os.Args) > 1 && os.Args[1] == "ent" {
+		ent = true // restrict to enterprise users
+	}
+	f, err := os.Open("/Users/sameer/Downloads/developer_survey_2019/survey_results_public.csv")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+	r := csv.NewReader(f)
+	var (
+		schema                      map[string]int
+		all, gcp, aws, azure, cloud langCounts
+	)
+	for {
+		rec, err := r.Read()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			log.Fatal(err)
+		}
+		if schema == nil {
+			schema = make(map[string]int)
+			for i, field := range rec {
+				schema[field] = i
+			}
+			continue
+		}
+		if ent && rec[schema["OrgSize"]] != "10,000 or more employees" {
+			continue
+		}
+		all.N++
+		var Go, Java bool
+		langs := strings.Split(rec[schema["LanguageWorkedWith"]], ";")
+		for _, lang := range langs {
+			switch lang {
+			case "Go":
+				all.Go++
+				Go = true
+			case "Java":
+				all.Java++
+				Java = true
+			}
+		}
+		plats := strings.Split(rec[schema["PlatformWorkedWith"]], ";")
+		var Cloud bool
+		for _, plat := range plats {
+			switch plat {
+			case "Google Cloud Platform":
+				gcp.N++
+				Cloud = true
+				if Go {
+					gcp.Go++
+				}
+				if Java {
+					gcp.Java++
+				}
+			case "AWS":
+				aws.N++
+				Cloud = true
+				if Go {
+					aws.Go++
+				}
+				if Java {
+					aws.Java++
+				}
+			case "Microsoft Azure":
+				azure.N++
+				Cloud = true
+				if Go {
+					azure.Go++
+				}
+				if Java {
+					azure.Java++
+				}
+			}
+		}
+		if Cloud {
+			cloud.N++
+			if Go {
+				cloud.Go++
+			}
+			if Java {
+				cloud.Java++
+			}
+		}
+	}
+	fmt.Printf("all %s\n", all.String(all.N))
+	fmt.Printf("gcp %s\n", gcp.String(all.N))
+	fmt.Printf("aws %s\n", aws.String(all.N))
+	fmt.Printf("azure %s\n", azure.String(all.N))
+	fmt.Printf("cloud %s\n", cloud.String(all.N))
+
+	fmt.Printf("P(GCP|Go) = P(GCP,Go)/P(Go) = %.1f/%.1f%% = %.1f%% vs P(GCP|Java) = %.1f%% vs P(GCP) = %.1f%%\n",
+		pct(gcp.Go, all.N), pct(all.Go, all.N), pct(gcp.Go, all.Go), pct(gcp.Java, all.Java), pct(gcp.N, all.N))
+	fmt.Printf("P(AWS|Go) = P(AWS,Go)/P(Go) = %.1f/%.1f%% = %.1f%% vs P(AWS|Java) = %.1f%% vs P(AWS) = %.1f%%\n",
+		pct(aws.Go, all.N), pct(all.Go, all.N), pct(aws.Go, all.Go), pct(aws.Java, all.Java), pct(aws.N, all.N))
+	fmt.Printf("P(Azure|Go) = P(Azure,Go)/P(Go) = %.1f/%.1f%% = %.1f%% vs P(Azure|Java) = %.1f%% vs P(Azure) = %.1f%%\n",
+		pct(azure.Go, all.N), pct(all.Go, all.N), pct(azure.Go, all.Go), pct(azure.Java, all.Java), pct(azure.N, all.N))
+	fmt.Printf("P(Cloud|Go) = P(Cloud,Go)/P(Go) = %.1f/%.1f%% = %.1f%% vs P(Cloud|Java) = %.1f%% vs P(Cloud) = %.1f%%\n",
+		pct(cloud.Go, all.N), pct(all.Go, all.N), pct(cloud.Go, all.Go), pct(cloud.Java, all.Java), pct(cloud.N, all.N))
+}
+
+type langCounts struct {
+	N    int
+	Go   int
+	Java int
+}
+
+func (c langCounts) String(n int) string {
+	return fmt.Sprintf("Total %d (%.1f%%)  Go %d (%.1f%% of Total, %.1f%% of all)  Java %d (%.1f%% of Total, %.1f%% of all)",
+		c.N, pct(c.N, n),
+		c.Go, pct(c.Go, c.N), pct(c.Go, n),
+		c.Java, pct(c.Java, c.N), pct(c.Java, n))
+}
+
+func pct(a, b int) float64 {
+	return math.Round(1000*float64(a)/float64(b)) / 10
+}