Podcast
Questions and Answers
What is the primary purpose of using arrays in programming as described?
What is the primary purpose of using arrays in programming as described?
- To handle lists of data efficiently. (correct)
- To perform mathematical operations directly.
- To improve the performance of string manipulations.
- To create a variable without any assigned values.
How is an array initialized in JavaScript according to the provided example?
How is an array initialized in JavaScript according to the provided example?
- An array is initialized using open and close brackets with no values. (correct)
- The array needs a lengthy declaration without brackets.
- An array is initialized using curly braces with values inside.
- Array can be initialized using the Array constructor only.
What is the index value of 'Salami' in the given groceries array?
What is the index value of 'Salami' in the given groceries array?
- 3 (correct)
- 2
- 0
- 4
What would happen if an index value exceeds the length of an array?
What would happen if an index value exceeds the length of an array?
Which of the following is a correct method to access 'Juice' from the groceries array?
Which of the following is a correct method to access 'Juice' from the groceries array?
What does the length property of an array represent?
What does the length property of an array represent?
What happens when an item is added to the beginning of the array using the unshift method?
What happens when an item is added to the beginning of the array using the unshift method?
What is the effect of calling the pop method on an array?
What is the effect of calling the pop method on an array?
Which of the following correctly describes the process of looping through an array from start to finish?
Which of the following correctly describes the process of looping through an array from start to finish?
If an array named groceries has an initial length of 5, what will its length be after executing groceries.push('Cookies')?
If an array named groceries has an initial length of 5, what will its length be after executing groceries.push('Cookies')?
What value is returned by the shift method when called on an array?
What value is returned by the shift method when called on an array?
What does the pop method return when called on an array?
What does the pop method return when called on an array?
How does the slice method affect the original array?
How does the slice method affect the original array?
What result do both indexOf and lastIndexOf methods return when searching for an item that does not exist in the array?
What result do both indexOf and lastIndexOf methods return when searching for an item that does not exist in the array?
What is the primary difference between indexOf and lastIndexOf?
What is the primary difference between indexOf and lastIndexOf?
What happens to the index positions of items in an array after using the shift method?
What happens to the index positions of items in an array after using the shift method?
What is the resulting length of an array after calling the unshift method with one item?
What is the resulting length of an array after calling the unshift method with one item?
When using the slice method with parameters (1, 4), which items are included in the new array?
When using the slice method with parameters (1, 4), which items are included in the new array?
What will be the value of goodAndBad after executing var goodAndBad = good.concat(bad);?
What will be the value of goodAndBad after executing var goodAndBad = good.concat(bad);?
What will the value of temperature be after executing var temperature = −42;?
What will the value of temperature be after executing var temperature = −42;?
Which of the following correctly uses the modulus operator?
Which of the following correctly uses the modulus operator?
How would i be modified after executing i = i - 2; if i was originally 100?
How would i be modified after executing i = i - 2; if i was originally 100?
What is the correct order of operations used by JavaScript when evaluating mathematical expressions?
What is the correct order of operations used by JavaScript when evaluating mathematical expressions?
Which expression correctly illustrates incrementing a variable i by 1?
Which expression correctly illustrates incrementing a variable i by 1?
Flashcards
Array
Array
An ordered list of values (elements).
Array Element
Array Element
A single value within an array.
Array Index
Array Index
A number that identifies the position of an element in an array.
Array Literal Notation
Array Literal Notation
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Accessing Array Values
Accessing Array Values
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Array Length
Array Length
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Empty Array
Empty Array
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Array Initialization
Array Initialization
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Array.shift()
Array.shift()
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Array.push()
Array.push()
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Array.unshift()
Array.unshift()
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Array.pop()
Array.pop()
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Array.slice()
Array.slice()
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Array.indexOf()
Array.indexOf()
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Array.lastIndexOf()
Array.lastIndexOf()
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Array Concatenation
Array Concatenation
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Array Length
Array Length
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Array index
Array index
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concat() method
concat() method
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Numbers in JavaScript
Numbers in JavaScript
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Accessing array values
Accessing array values
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Looping through arrays
Looping through arrays
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JavaScript Operators
JavaScript Operators
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Adding items (push)
Adding items (push)
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Order of Operations
Order of Operations
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Incrementing a Variable
Incrementing a Variable
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Adding items (unshift)
Adding items (unshift)
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Removing items (pop)
Removing items (pop)
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Decrementing a Variable
Decrementing a Variable
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Cumulative Modification
Cumulative Modification
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Removing items (shift)
Removing items (shift)
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Array push return value
Array push return value
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Undefined error
Undefined error
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Study Notes
Advanced Web Programming - Chapter 9: Arrays, Numbers
- Arrays: Used to handle lists of data.
- Array Properties: Used for common data list tasks.
- Numbers: Covers different numerical types (e.g., integers, decimals, complex, hexadecimal).
- Math Object: Provides mathematical functions and constants.
Arrays
- Real-World Example: A grocery list is a real-world example of an array.
- Array Values (or Elements): The items in the list that need to be purchased.
- Array Literal Notation: Using brackets
[]to create an array.
Creating Arrays
- Empty Arrays: Initialize an array with empty brackets
[]. Eg:var groceries = []; - Non-Empty Arrays: Create an array with values inside the brackets, separated by commas. Eg:
var groceries = ["milk", "eggs", "frosted flakes"];
Accessing Array Values
- Index Values: Each item in an array has a numerical index value, starting from 0. Eg:
groceries[0](milk),groceries[1](eggs). - Index Value Specification: Access an element by using its index value inside square brackets. Example:
groceries[1]
Accessing Multiple Values
- Iteration using for loop: The for loop can access all items in the array systematically.
- Length Property: Use the
lengthproperty of an array to determine its length and iterate across each element of the array up to element prior to thelengthof the array Examplegroceries.length
Adding Items to Arrays
- Push Method: Adds new items to the end of an array. Eg:
groceries.push("bananas"); - Unshift Method: Adds new items to the beginning of an array. Eg:
groceries.unshift("yogurt");
Removing Items from Arrays
- Pop Method: Removes and returns the last item in an array. Eg:
lastItem = groceries.pop(); - Shift Method: Removes and returns the first item in an array. Eg:
firstItem = groceries.shift();
Merging Arrays
- Concat Method: Combines two arrays into a new array, preserving the order. Eg.
var goodAndBad = good.concat(bad);
Numbers (JavaScript)
- Variables using Numbers: Declare variables containing numbers. Examples:
var stooges = 3;// integervar pi = 3.14159;// decimalvar color= 0x000;// hexvar massOfEarth = 5.9742e+24;// scientific notation
Numbers - Operators
- Mathematical Operators: The
+,-,*,/for fundamental operations on numbers.%for remainder (modulus). - Parentheses for Order of Operations: Operations within parentheses are performed first.
Incrementing and Decrementing
- Incrementing: Increasing a number's value.
- Decrementing: Decreasing a number's value.
- Increment/Decrement Operators:
++iori++– increment operator and--iori--– decrement operator. Use the operator at the start or end of the variable to adjust the order in which the calculation is performed.
Special Values
- NaN: "Not a Number." Result of invalid numerical operation
- Infinity/Infinity: Represent very large or small numbers respectfully. Return when you divide a number by zero.
The Math Object
- Functions: Provides various mathematical functions (e.g.,
sin,cos,tan,sqrt,pow). - Constants: Includes common mathematical constants (e.g.,
Math.PI,Math.E).
Rounding Numbers
- Rounding Functions:
Math.round(),Math.ceil(),Math.floor().
Trigonometric Functions
- Radians: Trigonometric functions, sin, cos, tan use radians as the input measurement.
- Convert Degrees to Radians: Convert to the appropriate unit before calculating trigonometric values.
Powers and Square Roots
- Math.pow(): Raise a number to a power. Eg.
Math.pow(2, 4);(2 to the power of 4) - Math.exp(): Raise Euler's constant (e) to a power.
- Math.sqrt(): Calculate the square root of a number.
Absolute Value
- Math.abs(): Return absolute value of a number.
Random Numbers
- Math.random(): Returns pseudo random values between 0 and 1.
Lab Exercises
- Reference links for further practice and understanding.
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Description
Explore Chapter 9 of Advanced Web Programming, where you will dive into arrays and numbers. This chapter covers the properties of arrays, how to create and access them, along with different numerical types and mathematical functions. Prepare to enhance your programming skills with practical examples and deeper insights into handling data efficiently.
