This is a list of how to create hash maps and use them in different languages. Not much fun here, more of a reference for me. Might add more content here later.

Java

Basic

// import
import java.util.HashMap;

// create, no type arguments needed to constructor (should work since java 7)
HashMap<String, String> myMap = new HashMap<>(); 

// insert
myMap.put("drink", "water");

// get
myMap.get("drink");

Go

(Yes, Golang map is implemented as a hash table/map)

Basic

// create 
var myMap = make(map[string]string)

// insert
myMap["drink"] = "water"

// get
myMap["drink"]

Rust

Basic

// import
use std::collections::HashMap;

// create, types are inferred
let mut my_map = HashMap::new();

// insert
my_map.insert(
    "drink".to_string(),
    "water".to_string(),
);

// get
my_map["drink"];

Basic

Python

(Same here, internally python dicts are hash maps/tables)

# create an empty dict
dict = {}

# insert
dict["drink"] = "water"

# get
dict.get("drink")
# or
dict["drink"]

C++

Basic

// include
#include <map>
#include <string>

// create
std::map<std::string, std::string> myMap;

// insert (will overwrite old value, if any)
myMap["drink"] = "water";
// or (will not overwrite, instead ignores new value)
myMap.insert(std::make_pair("dring", "water"));

// get
myMap["drink"];

Static initialization of member map

mapclass.h:

#include <map>
#include <string>

class MapClass {
public:
  static std::map<std::string, int> theMap;
  MapClass();
};

main.cc:

#include "mapclass.h"
#include <iostream>

std::map<std::string, int> MapClass::theMap = {
{"x", 1}
};

int main (int argc, char *argv[])
{
  std::cout << MapClass::theMap["x"] << std::endl;
  return 0;

returns 1