Working with arrays Array Basics Looping Through Arrays

Working with arrays Array Basics Looping Through Arrays Modifying Arrays Sorting Arrays Using Multidimensional Arrays

Array Basics • Arrays are collections of related values • the data submitted from a form, • the names of students in a class, • the populations of a list of cities. An array is a container that holds multiple values, each distinct from the rest. • Made up of elements • Each elements has key and value • Only one element with the given key •

• Arrays and other non-scalar values can’t be keys but they can be elements • Element value can be strings, numbers, true or false or can be other array

Creating arrays

Creating arrays with array()

Choosing a good arrayname • Follow same rules as variables names • Scalars and array cannot have the same names • $a cannot be of both scalar and array type

Numeric array • Arrays with numeric keys • Also called indexed or ordered array • Keys signify the position

Creating a numeric array

Adding elements with []

Finding the Size of an. Array

Looping through arrays • foreach() • works only on arrays • used to loop through each key/value pair • Syntax • foreach ($array as $value) { code to be executed; } • for() • used when you know in advance how many times the script should run • Syntax • for (init counter; test counter; increment counter) { code to be executed; }

Looping with foreach()

Alternating table rows colors

Modifying an array with foreach()

Using foreach( ) with numericarrays

Iterating througha numeric array with for( )

Alternating table row colors with for()

Array element order and foreach()

• To guarantee that elements are accessed in numerical key order, use for( )

Checking for an element with a particularkey

Checking for an element with aparticular value

Modifying Arrays • Operating on array elements • Interpolating array element values in double-quoted strings • Interpolating array element values with curly braces • Making a string from an array with implode( ) • Printing HTML table rows with implode( ) • Turning a string into an array with explode( )

Operating on arrayelements

Interpolating array element values indoublequoted strings

Interpolating array element values withcurly braces

unset( )

implode • The implode() function returns a string from the elements of an array. • Syntax • implode(separator, array)

Making a string from an array with implode( )

Printing HTML table rowswith implode( )

Turning a string into an array with explode( )

Sorting Arrays • Sorting with sort( ) • Sorting with asort( ) • Sorting with ksort( ) • Sorting with arsort( )

Sorting with sort( )

Sorting with asort( )

Sorting with ksort( )

• rsort( ) • arsort( ) • krsort( ) • Sort the arrays in descending order or reverse alphabetical order

Sorting with arsort( )

Using Multidimensional Array • Creating multidimensional arrays with array( ) • Accessing multidimensional array elements • Manipulating multidimensional arrays • Iterating through a multidimensional array with foreach( ) • Iterating through a multidimensional array with for( )