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# Programming Basics - array, loops, funcitons

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• ----- Meeting Notes (12/28/11 19:20) -----
• ### Programming Basics - array, loops, funcitons

1. 1. TRIVUz Academy PF03 Class Id:Programming Fundamentals MS Alam TRIVUz Founder, TRIVUz NetworkTRIVUz Academy
2. 2. TRIVUz AcademyRecap PF01 & PF02 TRIVUz Academy
3. 3. Recap We Define Computer & Programming Programming Process Programming Language Inputs & Outputs Define Logical Processing Variables Data Types Define Conditional StatementProgramming Fundamentals If… Then… Else… TRIVUz Academy PHP Operators www.trivuzacademy.com
4. 4. We are going to learn Variable+ Array Array Functions Global Array Loop for, do…while, for each FunctionsProgramming Fundamentals TRIVUz Academywww.trivuzacademy.com
5. 5. Variable+ ArrayTRIVUz Academy
6. 6. ArrayWhat is an Array?A variable is a storage area holding a number ortext. The problem is, a variable will hold only onevalue. TRIVUz Academy
7. 7. ArrayWhat is an Array?A variable is a storage area holding a number ortext. The problem is, a variable will hold only onevalue.An array is a special variable, which can storemultiple values in one single variable. TRIVUz Academy
8. 8. ArrayWhat is an Array?• An array in PHP is a structure which maps keys (array element names) to values• The keys can specified explicitly or they can be omitted• If keys are omited, integers starting with 0 are keys• The value mapped to a key can, itself, be an array, so we can have nested arrays TRIVUz Academy
9. 9. ArrayWhat is an Array?Variable VS ArrayTRIVUz Academy
10. 10. ArrayWhat is an Array?Variable VS Array?In Variable:<?php \$student = “Farah”; \$student = “Tawhid”; \$student = “Jewel”;?> TRIVUz Academy
11. 11. ArrayWhat is an Array?Variable VS Array?In Array:<?php \$student = array(“Farah”,”Tawhid”,”Jewel”);?> TRIVUz Academy
12. 12. ArrayWhat is an Array?Variable VS Array?Array will create Variable index like\$student[0] = “Farah”;\$student[1] = “Tawhid”;\$student[2] = “Jewel”; TRIVUz Academy
13. 13. ArrayVery simple array and outputCode<?php \$student = array(“Farah”,”Tawhid”,”Jewel”); print_r(\$student);?>OutputArray ( [0] => Trivuz [1] => Tawhid [2] => Jewel ) TRIVUz Academy
14. 14. ArrayEcho value from arrayCode<?php echo \$student[0]; echo \$student[1];?>OutputFarahTawhid TRIVUz Academy
15. 15. ArrayChange Value in ArrayCode<?php \$student[0] = ”Trivuz”; \$student[2] = "Asif Islam”; print_r(\$student);?>OutputArray ( [0] => Trivuz[1] => Tawhid [2] => Asif Islam ) TRIVUz Academy
16. 16. ArraySpecifying an Array• A special function is used to specify arrays array()• Format of Usage array([key=>]value, …)• A key is either a string or a non-negative integer• A value can be anything• Format of associative array specification \$ages = array(“Huzaifa”=>22, “Tuhin”=>23) TRIVUz Academy
17. 17. ArraySpecifying an Array• Here is another associative (hash) array: \$ages[„Riaydh‟]=“24”; \$ages[„Piash‟]=“21”;• Implicit indices are integers, starting at 0 \$student = array(“Koushik”,”Tafsir”,”Eunus”);• Here is the same array written differently \$student[0] = “Koushik”; \$student[0] = “Tafsir”; \$student[0] = “Eunus”; TRIVUz Academy
18. 18. ArraySpecifying an Array• If and explicit integer index is followed by implicit indices, they follow on from the highest previous index • Here is an array indexed by integers 1,2,3 \$student = array(1=>“Avishek”,”Mehedi”,”Masud”); • Here is an array indexed by integers 1,5,6 \$student = array(5=>“Avishek”,1=>”Mehedi”,”Masud”);• Show output <?php print_r(\$student); ?> TRIVUz Academy
19. 19. ArraySpecifying an Array• A two-dimensional hash array \$result = array(“Farah“=>array(“Bangla”=>85,”English”=>78)); echo \$result[„Farah‟][„Bangla]; echo \$result[„Farah‟][„English‟];• A two-dimensional ordinary array \$heights = array(10,20,30,40,50),array(100,200)); echo \$heights[0][1]; // output : 20 echo \$heights[1][1]; // output : 200• Change a two-dimensional array value \$heights[0][0] = 130; \$heights[0][1] = 140; print_r(\$heights); // output : Array ( [0] => Array ( [0] => 130 [1] => 140 ) ) TRIVUz Academy
20. 20. Array FunctionsPHP provides a huge set of array-manipulation functions  array – Create an array  array_change_key_case – Returns an array with all string keys lowercased or uppercased  array_chunk – Split an array into chunks  array_count_values – Counts all the values of an array  array_diff – Computes the difference of arrays  array_filter – Filters elements of an array using a callback funciton  array_flip – Flip all the values of an array  array_fill – Fill and array with values  array_intersect – Computes the intersection of arrays  array_key_exists – Checks if the given key or index exists in the array  array_keys – Return all the keys of an array TRIVUz Academy
21. 21. Array FunctionsPHP provides a huge set of array-manipulation functions  array_map – Applies the callback to the elements of the given arrays  array_merge – Merge two or more arrays  array_merge_recursive – Merge two or more arrays recursively  array_multisort – Sort multiple or multi-dimensional arrays  array_pad – Pad array to the specified length with a value  array_pop – Pop the element off the end of array  array_push – Push one or more elements onto the end of array  array_rand – Pick one or more random entries out of an array  array_reverse – Return an array with elements in reverse order  array_reduce – Iteratively reduce the array to a single value using a callback function  array_shift – Shift an element off the beginning of array  array_slice – Extract a slice of the array TRIVUz Academy
22. 22. Array FunctionsPHP provides a huge set of array-manipulation functions  array_splice – Remove a portion of the array and replace it with something else  array_sum – Calculate the sum of values in an array  array_unique – Remove duplicate values from an array  array_unshift – Prepend one or more elements to the beginning of array  array_values – Return all the values of an array  array_walk – Apply a user function to every member of an array  arsort – Sort an array in reverse order and maintain index association  asort – Sort an array and maintain index association  compact – Create array containing variables and their values  count – Count element in a variable  current – Return the current element in an array TRIVUz Academy
23. 23. Array FunctionsPHP provides a huge set of array-manipulation functions  each – Return the current key and value pair from an array and advance the array cursor  end – Set the internal pointer of an array to its last element  extract – Import variables into the current symbol table from an array  in_array – Return TRUE if a value exists in an array  Array_search – Searches the array for a given value and returns the corresponding key if successful  key – Fetch a key from an associative array  krsort – Sort an array by key  list – Assign variables as if they were an array  natsort– Sort an array using a “natural order” algorithm  pos – Get the current element from an array  prev – Rewind the internal array pointer TRIVUz Academy
24. 24. Array FunctionsPHP provides a huge set of array-manipulation functions  range – Create an array containing a range of elements  reset – Set the internal pointer of an array to its first element  rsort – Sort an array in reverse order  shuffle – Shuffle an array  sizeof – Get the number of elements in variable  sort – Sort an array  uasort – Sort an array with a user-defined comparison function  uksort – Soft an array by keys using a user-defined comparison function  usoft– Soft an array by values using a user-defined comparison function TRIVUz Academy
25. 25. Global ArrayGlobal Arrays  PHP Creates 6 global arrays that contain EGPCS (ENVIRONMENT, GET, POST, COOKIES and SERVER) information  PHP also creates a variable called \$_REQUEST that contains all the information in the 6 global arrays  PHP also creates a variable called \$PHP_SELF that contains the name of the current script (relative to the doc root)  \$_ENV – Contains the values of any environment variables, such as the browser version  Eg: \$_ENV[HTTP_USER_AGENT]  \$_FILES – Contains information about any files submitted  \$_COOKIES – Contain any cookies submitted as name value pairs  \$_SERVER – Contains useful information about the webserver TRIVUz Academy
26. 26. Global Array\$_SERVER Keys  [DOCUMENT_ROOT]  [SERVER_SOFTWARE]  [HTTP_*]  [COMSPEC]  [PHP_SELF]  [GATEWAY_INTERFACE]  [QUERY_STRING]  [PATHEXT]  [REMOTE_ADDR]  [PATH]  [REQUEST_METHOD]  [REMOTE_PORT]  [REQUEST_URI]  [SERVER_ADDR]  [SCRIPT_FILENAME]  [SERVER_ADMIN]  [SCRIPT_NAME]  [SERVER_SIGNATURE]  [SERVER_PORT]  [SystemRoot]  [SERVER_PROTOCOL]  [WINDIR] TRIVUz Academy
27. 27. Control Structure LoopingTRIVUz Academy
28. 28. Control Structure Looping Loops execute a block of code a specified number of times, or while a specified condition is true. PHP loops are control structures and you can use them the execute a code block more times. It means you dont have to copy and paste your code many times in the file just use a right loop statement. TRIVUz Academy
29. 29. Control Structure LoopingA basic example:<?php echo " 1 ”; echo " 2 ”; echo " 3 ”; echo " 4 ”; echo " 5 ”;?> TRIVUz Academy
30. 30. Control Structure LoopingA basic example:<?php echo " 1 ”; echo " 2 ”; echo " 3 ”; echo " 4 ”; echo " 5 ”;?>With a for loop it looks like this:<?php for (\$i=1; \$i <= 5; \$i++) { echo “ \$i “;}?> TRIVUz Academy
31. 31. Control Structure Looping In PHP, we have the following looping statements:  While  Do…while  For  foreach TRIVUz Academy
32. 32. Control Structure while loopSyntaxwhile TRIVUz Academy
33. 33. Control Structure while loopSyntaxwhile (condition) TRIVUz Academy
34. 34. Control Structure while loopSyntaxwhile (condition){ // code to be executed;} TRIVUz Academy
35. 35. Control Structure while loopExample<?php\$i = 1;while (\$i < 5) { echo “ I = “ . \$i . “<br />”; echo \$i++; }?> TRIVUz Academy
36. 36. Control Structure while loopExecutionCode:<?php\$i = 1;while (\$i < 5) { echo “ Value of I is now “ . \$i . “<br />”; echo \$i++; }?> TRIVUz Academy
37. 37. Control Structure while loopExecution (Loop - 1)Code:<?php\$i = 1;while (\$i < 5) // \$i is now 1 { echo “ Value of I is now “ . \$i . “<br />”; echo \$i++; // \$i is now 2 }?>Output: Value of I is now 1 TRIVUz Academy
38. 38. Control Structure while loopExecution (Loop - 2)Code:<?php\$i = 1;while (\$i < 5) // \$i is now 2 { echo “ Value of I is now “ . \$i . “<br />”; echo \$i++; // \$i is now 3 }?>Output: Value of I is now 1 Value of I is now 2 TRIVUz Academy
39. 39. Control Structure While LoopExecution (Loop - 3)Code:<?php\$i = 1;while (\$i < 5) // \$i is now 3 { echo “ Value of I is now “ . \$i . “<br />”; echo \$i++; // \$i is now 4 }?>Output: Value of I is now 1 Value of I is now 2 Value of I is now 3 TRIVUz Academy
40. 40. Control Structure while loopExecution (Loop - 4)Code:<?php\$i = 1;while (\$i < 5) // \$i is now 4 { echo “ Value of I is now “ . \$i . “<br />”; echo \$i++; // \$i is now 5 }?>Output: Value of I is now 1 Value of I is now 2 Value of I is now 3 Value of I is now 4 TRIVUz Academy
41. 41. Control Structure while loopExecution (Loop - 4)Code:<?php\$i = 1;while (\$i < 5) // \$i is now 5 { echo “ Value of I is now “ . \$i . “<br />”; echo \$i++; // not executed } // next code to execute?>Output: Value of I is now 1 Value of I is now 2 Value of I is now 3 Value of I is now 4 TRIVUz Academy
42. 42. Control Structure do…while loopSyntaxdo { // code to be executed; }while (condition); TRIVUz Academy
43. 43. Control Structure do…while loopExampledo { \$i++; echo “The number is “ . \$i . “<br />”; }while (\$i < 5); TRIVUz Academy
44. 44. Control Structure for loopSyntaxfor (init; condition; increment){ // code to be executed;} TRIVUz Academy
45. 45. Control Structure for loopExamplefor (\$i = 1; \$i < 5; \$++){ echo “Current value of I is “ . \$i . “<br />”;} TRIVUz Academy
46. 46. Control Structure for eachFOREACH is used in PHP to loop over all elements of an array. The basicsyntax of FOREACH is as follows:FOREACH (\$array_variable as \$value){ //code to execute}orFOREACH (\$array_variable as \$key => \$value){ //code to execute} TRIVUz Academy
47. 47. Control Structure for eachSimple Syntaxforeach (array_expression as \$value) // statementforeach (array_expression as \$key => \$value) // statement TRIVUz Academy
48. 48. Control Structure for eachExample<?php \$arr = array(1, 2, 3, 4); foreach (\$arr as &\$value) { \$value = \$value * 2;} // \$arr is now array(2, 4, 6, 8) unset(\$value); // break the reference with the last element?> TRIVUz Academy
49. 49. Control Structure for eachExample<?php \$arr = array("one", "two", "three"); reset(\$arr); while (list(, \$value) = each(\$arr)) { echo "Value: \$value<br />n”; } foreach (\$arr as \$value) { echo "Value: \$value<br />n”; }?> TRIVUz Academy
50. 50. Function What is function? How function help programmers? Types of functionTRIVUz Academy
51. 51. Function System Defined Function User Defined FunctionTRIVUz Academy
52. 52. Function User-Defined FunctionIn PHP, functions are defined in the following fashion:function function_name ([variable [= constant][,…]) { // any valid PHP code } TRIVUz Academy
53. 53. Function User-Defined FunctionExample: User-Defined Function to determine a Leap Year<?phpfunction is_leapyear (\$year = 2011) { \$is_leap = (!(\$year % 4) && ((\$year % 100) || !(\$year % 400))); return \$is_leap; }?> TRIVUz Academy
54. 54. Function User-Defined FunctionFunction with user defined argumentfunction function_name (\$arg) { // any valid PHP code } TRIVUz Academy
55. 55. Function User-Defined FunctionExample: User-Defined Function to determine a Leap Year<?phpfunction is_leapyear (\$year) { \$is_leap = (!(\$year % 4) && ((\$year % 100) || !(\$year % 400))); return \$is_leap; }?> TRIVUz Academy
56. 56. Function User-Defined FunctionExample: User-Defined Function to determine a Leap Year<?phpfunction is_leapyear (\$year) { \$is_leap = (!(\$year % 4) && ((\$year % 100) || !(\$year % 400))); return \$is_leap; }?>Calling the user defined function is_leapyear Is_leapyer(2008); Is_leapyer(2011); TRIVUz Academy
57. 57. Thank You MS Alam TRIVUz Founder, TRIVUz Academy trivuz@gmail.com