05
Karel the Robot
Java
Console Programs
Graphics Programs
Text Processing
Data Structures
GUIs
Defining our own Variable Types Where are we?<br>
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Collections High Level List: Array: Matrix: type[][] type[] ArrayList<type><br>
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Collections High Level List: Array: Matrix: int[][] double[] ArrayList<String><br>
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ArrayList
index -> value<br>
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Arrays
index -> value<br>
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Matrix
(row, col) -> value<br>
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Maps can have any type for key Many examples<br>
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HashMap
key -> value Can be any type<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”]<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”]<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values:<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values:<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values: “bark” “dog”<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values: “bark” “dog”<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow”<br>
20
Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] Keys: Values: “bark” “dog” “cat” “meow” animalSoundMap<br>
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Simple Example animalSoundMap Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
22
Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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Simple Example Make a new HashMap of animal sounds
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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Simple Example Make a new HashMap of animal sound
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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Simple Example Make a new HashMap of animal sound
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “cat”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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Simple Example Make a new HashMap of animal sound
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “cat”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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Simple Example Make a new HashMap of animal sound
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “cat”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>(); Key Type Value Type<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
animalSoundMap.put(“dog”, “bark”);<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
animalSoundMap.put(“dog”, “bark”);<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
animalSoundMap.put(“dog”, “bark”);<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
animalSoundMap.put(“dog”, “bark”);<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
animalSoundMap.put(“dog”, “bark”);
animalSoundMap.get(“dog”);<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
animalSoundMap.put(“dog”, “bark”);
animalSoundMap.get(“dog”);<br>
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My First Map HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
animalSoundMap.put(“dog”, “bark”);
animalSoundMap.get(“dog”);<br>
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My First Map Make a new HashMap of animal sound
2. Add elements:
Put [key = “dog”, value = “bark”]
Put [key=“cat”, value=“meow”]
Put [key=“seal”, value=“ow ow ow”]
3. Get elements:
Get [key = “dog”] animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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My First Map animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow” // 1. Make a new map
HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
// 2. Put things into the map
animalSoundMap.put("dog", "woof");
animalSoundMap.put("cat", "meow");
animalSoundMap.put("seal", "ow ow ow");
// 3. Get things out of the map
animalSoundMap.get("dog"); // "woof”<br>
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My First Map // 1. Make a new map
HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
// 2. Put things into the map
animalSoundMap.put("dog", "woof");
animalSoundMap.put("cat", "meow");
animalSoundMap.put("seal", "ow ow ow");
// 3. Get things out of the map
animalSoundMap.get("dog"); // "woof"
animalSoundMap.get("fox"); // ? animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow”<br>
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brothers Vegard
and Bård Ylvisåker Circa 2013,
Norway<br>
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Ylvis – “The Fox”. Permission asked. Pending.<br>
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My First Map animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow” // 1. Make a new map
HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
// 2. Put things into the map
animalSoundMap.put("dog", "woof");
animalSoundMap.put("cat", "meow");
animalSoundMap.put("seal", "ow ow ow");
// 3. Get things out of the map
animalSoundMap.get("dog"); // "woof"
animalSoundMap.get("fox"); // ?<br>
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My First Map animalSoundMap Keys: Values: “bark” “dog” “cat” “meow” “seal” “ow
ow
ow” // 1. Make a new map
HashMap<String, String> animalSoundMap =
new HashMap<String, String>();
// 2. Put things into the map
animalSoundMap.put("dog", "woof");
animalSoundMap.put("cat", "meow");
animalSoundMap.put("seal", "ow ow ow");
// 3. Get things out of the map
animalSoundMap.get("dog"); // "woof"
animalSoundMap.get("fox"); // null<br>
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Make a HashMap
Put and get values into a map
Some useful other methods
int size = myMap.size();
myMap.containsKey(key); // returns true or false if key is in map
myMap.keySet();
myMap.remove(key); // make like a tree and leave!
Iterate using a foreach loop HashMap<keyType, valueType> myMap =
new HashMap<keyType, valueType>(); myMap.put(key, value);
myMap.get(key) // returns the corresponding value for(keyType key : myMap.keySet()){ // not ordered
myMap.get(key); // do something with the key/value pair } HashMaps on one slide<br>
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Phone Book 6701678 addToPhoneBook printPhoneBook lookup<br>
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Make a keyboard keyboardC.txt<br>
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Core
Understanding Advanced
Understanding Good Work so Far<br>
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Why is this so fast?<br>
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Why is this so fast? int hash(string key); * Learn more in CS106B<br>
