kentquirk

package main

import "fmt"

type Pet struct {
	Owner string `json:"owner"`
	Pet   string `json:"pet"`
}

func main() {

kentquirk

// requires lodash.js
var output = {}
_.each(input, function(element){
    a = _.get(output, element.owner, [])
    a.push(element.pet)
    output[element.owner] = a
})

kentquirk

output = dict([[e["owner"], []] for e in input])
for element in input:
    output[element["owner"]].append(element["pet"])

kentquirk

output = dict()
for element in input:
    output[element["owner"]] = output.get(element["owner"], ()) + (element["pet"],)

kentquirk

output = dict()
for element in input:
    item = output.get(element["owner"], [])
    item.append(element["pet"])
    output[element["owner"]] = item

kentquirk

output = dict()
for element in input:
    try:
        output[element["owner"]].append(element["pet"])
    except KeyError:
        output[element["owner"]] = [element["pet"]]

kentquirk

output = {}
for element in input:
    if output.has_key(element["owner"]):
        output[element["owner"]].append(element["pet"])
    else:
        output[element["owner"]] = [element["pet"]]

kentquirk

let output = {}
for (const element of input) {
  if (output.hasOwnProperty(element.owner)) {
    output[element.owner].push(element.pet)
  } else {
    output[element.owner] = [element.pet]
  }
}

kentquirk

var output = {}
input.forEach(function(element) {
  if (output.hasOwnProperty(element.owner)) {
    output[element.owner].push(element.pet)
  } else {
    output[element.owner] = [element.pet]
  }
});

kentquirk

var output = {}
for (var i=0; i<input.length; i++) {
  if (output[input[i].owner] == undefined) {
    output[input[i].owner] = [input[i].pet]
  } else {
    output[input[i].owner].push(input[i].pet)
  }
}