Map data type
A map is a collection of key-value pairs. Both the key and the value are strings.
The elements in a map are automatically sorted on their keys.
Constructors
Map Map()
Creates an empty map.
Map Map(String value)
Pass a String containing key-value pairs separated by "\n":
"key=value\nkey=value\nkey=value,..."
Map m = Map("roses = red\nviolets = blue");
Note
Don't add space between \n and the 1st character of the key!
Adding elements to maps
Map insert(String key, String value)
insert() adds a new key-value pair to the map.
Map m;
m.insert("Super", "Office");
Accessing elements in maps
Bool exists(String key)
exists() checks if the map contains the given key.
Map m = Map("height = 25\nwidth = 10\ndepth = 7");
String key = "height";
printLine(m.exists(key).toString());
Integer size()
size() counts the elements in the map and returns that number.
Map m = Map("height=25\nwidth=10\ndepth=7");
printLine(m.size().toString());
An empty map has size == 0.
Map m;
if (m.size() == 0) {
printLine("This map is empty");
}
String get(String key)
Returns the value for the given key.
Map m = Map("height=25\nwidth=10");
String key = depth;
printLine(m.get(key));
getKey() and getVal() also retrieve data from the map. These methods depend on the internal iterator of the map and are described in the Looping section.
String getWithFallback(String key, String fallback)
Returns the fallback value if key does not exist.
Map m = Map("height=25\nwidth=10");
printLine(m.getWithFallback("foo", "bar"));
Updating elements
When working with numeric strings, you can increment values stored in the map. The increment can be given as either Integer or Float.
In both cases, you provide the key to look up the element and the value to add to the currently stored value.
Void increaseValueForKey(String key, Integer value)
Map m = Map("height=25\nwidth=10");
m.increaseValueForKey("height", -5);
Void increaseValueForKey(String key, Float value)
Map m = Map("height=25\nwidth=10");
m.increaseValueForKey("width", 2.5);
Removing elements
You can remove either a specific element identified by its key, or you can remove all elements.
Void remove(String key)
Removes the element with the given key.
Map m = Map("roses = red\nviolets = blue");
m.remove("violets");
Void clear()
Removes all elements from the map.
Map m = Map("roses = red\nviolets = blue");
m.clear();
Looping maps
Looping (or iterating) maps is similar to looping an array. However, where you would declare and update the Integer iterator for the array index, Maps have a built-in iterator that you position.
Note
insert() resets the map iterator when called.
Bool eof()
Returns true if the map iterator has moved past the end of the map, otherwise false.
Map m;
if (m.eof()) {
printLine("You have reached the final frontier");
}
Note
That eof() returns true is not the same as the map is empty. It can be, but it doesn't have to be. Use size() to check if the map is truly empty.
Bool first()
Rewinds the internal iterator to the 1st element.
first() returns false if the map is empty.
Map m = Map("height=25\nwidth=10");
m.first();
Bool next()
Moves the map iterator to next position.
next() returns false if eof().
Map m = Map("height=25\nwidth=10");
m.next();
String getKey()
Returns the key pointed to by the map iterator.
Map m = Map("height=25\nwidth=10");
printLine(m.getKey());
String getVal()
Returns the value pointed to by the map iterator.
Map m = Map("height=25\nwidth=10");
printLine(m.getVal());
Putting it together
Map m = Map("height=25\nwidth=10");
m.first();
while (!m.eof()){
printLine(m.getKey() + " = " + m.getVal());
m.next();
}
JSON
You can convert both ways between Maps and JSON.
Format:
{"key": "value", "foo": "bar"}
String toJson()
Converts the Map to JSON.
Map m = Map("height=25\nwidth=10");
printLine(m.toJson());
Void fromJson(String json)
Converts a JSON string to a map.
String s = "{"depth":"7","height":"20","width":"12.500000"}";
Map m;
m.fromJson(s);