1 / 35

Arrays In PHP

Arrays In PHP. By: Junejo Naeem Ahmed. Arrays. Arrays are complex variables that store a group of values under a single variable name. An array is useful for storing a group of related values. Creating and Working with Arrays.

kawena
Download Presentation

Arrays In PHP

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Arrays In PHP By: JunejoNaeem Ahmed

  2. Arrays • Arrays are complex variables that store a group of values under a single variable name. • An array is useful for storing a group of related values.

  3. Creating and Working with Arrays • To create a variable, you assign a value to it. Similarly, the simplest way to create an array is to assign a value to it. • $customers[ 1 ] = “Ali”; • At this point, the array named $customers has been created and holds only one value — Ali. • Next, you use the following statements: • $customers[ 2 ] = “Ahmed”; • $customers[ 3 ] = “Hassan”; • Now, the array $customers contains three values: Ali , Ahmed, and Hassan.

  4. Creating and Working with Arrays … • An array can be viewed as a list of key/value pairs, stored as follows: • $arrayname[‘key1’] = value1; • $arrayname[‘key2’] = value2; • $arrayname[‘key3’] = value3; • and so on up to any number of elements in the array. • The key is also referred to as the index.

  5. Creating and Working with Arrays … • Arrays can use either numbers or strings for keys. In the $customers array, the keys are numbers — 1, 2, and 3. • However, you can also use strings for keys. • For example, the following statements create an array of state capitals: • $capitals[‘Sindh’] = “Karachi”; • $capitals[‘Punjab’] = “Lahore”; • $capitals[‘Baluchistan’] = “Quetta”;

  6. Creating and Working with Arrays … • Or you can use shortcuts to create arrays, rather than write separate assignment statements for each number. • One shortcut uses the following statements: • $customers[] = “Ali”; • $customers[] = “Ahmed”; • $customers[] = “Hassan”; • When you create an array by using this shortcut, the values are automatically assigned keys that are serial numbers, starting with the number 0.

  7. Creating and Working with Arrays … • An even shorter shortcut is to use the following statement: • $customers = array ( “Ali”,”Ahmed”,”Hassan”); • $ customers = array ( 1 => “Ali”,” Ahmed”,” Hassan”); • You can also create an array with a range of values by using the following statement. • $years = range(2001, 2010);

  8. Viewing arrays • You can see the structure and values of any array by using one of two statements — var_dump or print_r. • The print_r() statement, however,gives somewhat less information. • To display the $customers array, use the following statement: • print_r($customers); • To get more information, use the following statement. • var_dump($customers);

  9. Modifying arrays • Arrays can be changed at any time in the script, just as variables can. • The individual values can be changed, elements can be added or removed, and elements can be rearranged. • $customers[2] = “John”; • $customers[4] = “Hidaya”; • $customers[] = “Dell”; • You can also copy an entire existing array into a new array with this statement: • $customerCopy = $customers;

  10. Removing values from arrays • Sometimes you need to completely remove a value from an array. • $colors = array ( “red”, “green”, “blue”, “pink”, “yellow” ); • $colors[ 3 ] = “”; • Although this statement sets $colors[3] to blank, it does not remove it from the array. You still have an array with five values, one of the values being an empty string. • To totally remove the item from the array, you need to unset it. • unset($colors[3]);

  11. Removing values from arrays • Removing all the values doesn’t remove the array itself • To remove the array itself, you can use the following statement • unset($colors);

  12. Finding Array Size • You can find out the size of your array by using either the count statement or a sizeof statement. • The format for these statements is as follows • $n = count($arrayname); • $n = sizeof($arrayname); • After either of these statements, $n will contain the number of elements in the array.

  13. Using Arrays in Statements • Arrays can be used in statements in the same way that variables are used in. • You can retrieve any individual value in an array by accessing it directly, as in the following example: • $Sindhcapital = $capitals[‘Sindh’]; • echo $Sindhcapital;

  14. Using arrays in echo statements • You can echo an array value like this: • echo = $capitals[‘Sindh’];

  15. Using arrays in list statements • You can retrieve several values at once from an array with the list statement. • The list statement copies values from an array into variables. • $colors=array(“red”,”green”); • List($red,$green)=$colors;

  16. Retrieve the key from an array • In some cases, you may want to retrieve the key from an array element rather than the value. • Suppose the following element is the first element in an array: • $capitals[‘Sindh’] = “Karachi”; • $value = $capitals[‘Sindh’]; • $key = key($capitals); • echo “$key: $value”;

  17. Walking through an Array • Walking through each and every element in an array, in order, is called iteration. • It is also sometimes called traversing. • Two ways to walk through an array: • Traversing an array manually: Uses a pointer to move from one array value to another. • Using foreach: Automatically walks through the array, from beginning to end, one value at a time.

  18. Traversing an array manually • current($arrayname): Refers to the value currently under the pointer. • next($arrayname): Moves the pointer to the value after the current value. • previous($arrayname): Moves the pointer to the value before the current pointer location. • end($arrayname): Moves the pointer to the last value in the array. • reset($arrayname): Moves the pointer to the first value in the array.

  19. Using foreach to walk through an array • You can use foreach to walk through an array one value at a time and execute a block of statements by using each value in the array. • The general format is as follows: • foreach ( $arraynameas $keyname=> $valuename) • { • block of statements; • }

  20. Converting Arrays into Strings (And Vice Versa) • You can create an array that contains the contents of a string by using a statement in the following format: • $arrayname = explode(“s”,string); • Conversely, you can convert an array into a string by using the following statement: • $resString = implode(“s”,$array);

  21. Splitting Arrays • You can split an array by creating a new array that contains a subset of an existing array. • You can do this by using a statement of the following general format: • $subArray = array_slice($arrayname,n1,n2);

  22. Merging Arrays • Conversely, you can merge two or more arrays together by using the following statement: • $bigArray = array_merge($array1,$array2,...);

  23. Summing arrays • To add all the values in an array, use the following statement: • $sum = array_sum($array); • Of course, you are only going to add elements in an array of numbers. • PHP converts strings to 0 if you try to add them.

  24. Removing duplicate items • $names2 = array_unique($names);

  25. Exchanging keys and values • To exchange the values, use the following statement: • $arrayFlipped = array_flip($testarray);

  26. Multidimensional Arrays • I describe arrays that are a single list of key/value pairs. • However, on some occasions, you may want to store values with more than one key.

  27. Creating multidimensional arrays • You can create multidimensional arrays in the same ways you create one dimensional arrays. • $foodPrices[‘vegetable’][‘potato’] = 1.00; • $foodPrices[‘fruit’][‘apple’] = 2.50; • You can also use a shortcut and allow PHP to choose the keys, as follows: • $foodPrices[‘vegetable’][ ] = 1.00; • $foodPrices[‘fruit’][ ]= 2.50;

  28. Viewing multidimensional arrays • You can view a multidimensional array in the same ways you can view any array — by using the print_r or the var_dump statements.

  29. Using multidimensional arrays in statements • You can get values from a multidimensional array by using the same procedures that you use with a one-dimensional array. • you can access a value directly with this statement: • $hamPrice = $foodPrices[‘vegetable’][‘potato’] • You can also echo the value: • echo $foodPrices[‘vegetable’][‘potato’]

  30. Sorting Arrays • One of the most useful features of arrays is that PHP can sort them for you. • PHP originally stores array elements in the order in which you create them. • PHP can sort arrays in a variety of ways. • To sort an array that has numbersas keys, use a sort statement as follows: • sort($arrayname); • This statement sorts arrays by the values and assigns new keys that are the appropriate numbers. • The values are sorted with numbers first, uppercase • letters next, and lowercase letters last.

  31. Sorting Arrays • If you use sort() to sort an array with words as keys, the keys are changed to numbers, and the word keys are thrown away. • To sort arrays that have words for keys, use the asort statement as follows: • asort($capitals);

  32. Ways You Can Sort Arrays • sort($arrayname) Sorts by value; assigns new numbers as the keys. • asort($arrayname) Sorts by value; keeps the same key. • rsort($arrayname) Sorts by value in reverse order; assigns new numbers as the keys. • arsort($arrayname) Sorts by value in reverse order; keeps the same key. • ksort($arrayname) Sorts by key. • krsort($arrayname) Sorts by key in reverse order.

  33. Assigments Make a page having one textbox if a user enter value suppose 2 than on next page make dynamic 2 fieldsets having username,Address and Gender contact, nic and while entering in contact textbox here user is capable of entering more than 1 contacts seperated each contact through comma on submit these values should be stored in array and shown on third page.

  34. Assigments • Take an unsorted array and sort it using bubble sort technique. • Make an array which should contain intersected values of two given arrays. • Take an input of NICs of students applying for two different departments of an educational institute, there should be a form to collect the data of students. After submitting the form, we should be able to Detect those students who applied in more then one departments.

More Related