App Lab Documentation

getValue

Category:Variables

Gets the value associated with a specific key in an object.

An object is a way to collect data and assign a unique label to each item. One example of a real-life object is a dictionary - every word has a corresponding definition. Here's how a dictionary would look as an App Lab object:

var dictionary = {
	"tortilla": "a thin, flat pancake of cornmeal or flour, eaten hot or cold, typically with a savory filling as a part of Mexican cuisine.",
    "naan": "a type of leavened bread, typically of teardrop shape and traditionally cooked in a clay oven as part of Indian cuisine.",
    "injera": "a white leavened Ethiopian bread made from teff flour, similar to a crêpe."
}

In the example above, each word in the dictionary is the key - it's what you use to look up values in the dictionary. The definitions are the values - they are what are trying to look up in the dictionary.

You can use getValue to look up a value from its key. This would be like looking up the definition of a word in the dictionary.

Examples

Dictionary Lookup

Use getValue() to look up the definition of words in a dictionary object

var dictionary = {
    "tortilla": "a thin, flat pancake of cornmeal or flour, eaten hot or cold, typically with a savory filling as a part of Mexican cuisine.",
    "naan": "a type of leavened bread, typically of teardrop shape and traditionally cooked in a clay oven as part of Indian cuisine.",
    "injera": "a white leavened Ethiopian bread made from teff flour, similar to a crêpe."
}

var definition = getValue(dictionary, "tortilla");
console.log("Tortilla: " + definition);
definition = getValue(dictionary, "naan");
console.log("Naan: " + definition);

Phone Number Lookup

Use a dictionary to look up someone's phone number

var phoneNumbers = {
	"Brendan": "520-555-1827",
    "Alicia": "510-555-9182",
    "Omar": "720-555-2817",
    "Emergency": "911"
};

var name = prompt("Enter the phone number you want to look up (Brendan, Alicia, Omar, Emergency)");
var number = getValue(phoneNumbers, name);
console.log(name + ": " + number);

Abbreviation Dictionary

Teach a chatbot what new abbreviations mean

var abbreviations = {
	"LOL": "Laugh out loud",
    "TIL": "Today I Learned",
    "LGTM": "Looks Good To Me",
    "FWIW": "For What It's Worth",
    "FYI": "For Your Information"
};

console.log("Hello! I am learning new abbreviations! Would you like to look up an abbreviation, or teach me a new one?);
var choice = prompt("(1) Look Up an Abbreviation (2) Teach a New Abbreviation);

if(choice == 1) {
	var word = prompt("What abbreviation do you want to look up?");
    var definition = getValue(abbreviations, word);
    console.log(word + ": " + definition);
}
if(choice == 2) {
	var word = prompt("What is the new abbreviation?");
    var definition = prompt("What does it mean?");
    addPair(abbreviations, word, definition);
    console.log("Successfully Added!");
}

Syntax

getValue(object, "key")

Parameters

Name	Type	Required?	Description
object	Object		The object to access the value from.
key	String		The name of the key to look up the value for in `object`.

Returns

The value stored in `object` under the label `key`.

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