highschool/Grade 10/Computer Science/ICS4U1/Array Manipulation Notes.md

Arrays

What is an Array?

• Object used to store a list of values

• All values in array are the same type -Eg. int, double, char, string, etc

• Used to store a large number of data

• Easy to access any element in the array

How to Declare

• Declaring an array to up to 10 words

String array[] = new String[10];

• Declaring an array and initializing variables at the same time:

String array[] = {"s", "d", "f"};

String Manipulataion

• ``length() to find the length of a string

• stringName.charAt(0) will output the first character

• Each character in a string has a positio. String positions start at 0

• stringName.indexOf("T") will output the index number that the letter T belongs to

• stringName.substring(3) will output all characters after the index #

• Eg. string stringName = "Jim hates math"

  • Output: hates math

• First # is for the index that you want and last number is for the index that you don’t wnat

• stringName2 = " i hate math "

• stringName2.trim(); - output: i hate math"

• stringName.toLowerCase() makes every character a lower case letter

• stringName.toUpperCase() makes every character an upper case letter

• concat()

• stringname1.concat(stringname2); will put both string into 1 word

• stringname.replce("a", "p"); will replace every 'a' with 'p'

• stringname1.equals(stringname2); will return true of false depending on whether the two contain the same value

• stringname1.compareTo(stringname2); is for alphabetical order

  • if the condition above is < 0, name1 is before name2. >0, name1 is before name2, if =0, its the same string