11b php programming

7/31/2019 11b PHP Programming

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PHP Programming: Functions,

Strings, Arrays, Date and Time

John Ryan B. Lorca

Instructor I

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Functions

A function is a block of code that can be executedwhenever we need it.

Creating PHP functions: All functions start with the word "function()"

Name the function - It should be possible to understandwhat the function does by

its name. The name can start with a letter or underscore(not a number)

Add a "{" - The function code starts after the opening curlybrace

Insert the function code

Add a "}" - The function is finished by a closing curly brace

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Functions

A simple function that writes my name when it iscalled:

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Functions

Now we will use the function in a PHP script:


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Functions

The output of the code will be:

Hello world!

My name is Marcus Oliver Graichen.

That's right, Marcus Oliver Graichen is my name.

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Functions

Our first function writeMyName() is a verysimple function. It only writes a static string.

To add more functionality to a function, we

can add parameters. A parameter is just like a variable.

You may have noticed the parentheses

(brackets!) after the function name, like: writeMyName(). The parameters are specified

inside the parentheses.

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Functions

The following example will write different firstnames, but the same last name:

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Functions


My name is John smith.

My name is Sarah Smith.

My name is Smith Smith.

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Functions

The following function has two parameters:

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Functions

The output of the code will be:My name is John Smith.

My name is Sarah Smith!

My name is Smith Smith...

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Functions

Functions can also be used to return values.

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Functions

The output of the code will be:1 + 16 = 17

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Exercise

Create a function that:

receives two (2) parameters:x(double) and y(double)

Performs the four fundamental operations: Addition

Subtraction

Muliplication

Division Displays result in this format:

x + y =

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Strings

String variables are used for values that contains characterstrings.

We are going to look at some of the most common functionsand operators used to

manipulate strings in PHP. After we create a string we can manipulate it. A string can be

used directly in a

function or it can be stored in a variable.

Below, the PHP script assigns the string "Hello World" to a

string variable called $txt:

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Strings

The output of the code will be:Hello World

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Strings

The Concatenation Operator

There is only one string operator in PHP.

The concatenation operator (.) is used to put two string values together.

To concatenate two variables together, use the dot (.) operator:

If we look at the code above you see that we used the concatenation

operator two times. This is because we had to insert a third string. Between the two string variables we added a string with a single

character, an empty space, to separate the two variables.

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Strings


Hello World 1234

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Strings

Using the strlen() function

The strlen() function is used to find the length of a string.

Let's find the length of our string "Hello world!":

The output of the code above will be:

12

The length of a string is often used in loops or otherfunctions, when it is important to know when the stringends. (i.e. in a loop, we would want to stop the loop afterthe last character in the string)

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Strings

Using the strpos() function

The strpos() function is used to search for a string or character within astring.

If a match is found in the string, this function will return the position ofthe first match.

If no match is found, it will return FALSE. Let's see if we can find the string "world" in our string:

The output of the code above will be:

6

As you see the position of the string "world" in our string is position 6. Thereason that

it is 6, and not 7, is that the first position in the string is 0, and not 1.

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Arrays

An array in PHP is actually an ordered map. A

map is a type that maps values to keys. This

type is optimized in several ways, so you can

use it as a real array, or a list (vector),hashtable (which is an implementation of a

map), dictionary, collection, stack, queue and

probably more. Because you can have anotherPHP array as a value, you can also quite easily

simulate trees.

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Arrays

Specifying with array()

An array can be created by the array() language-construct. It takes acertain number of comma-separated key => value pairs.

array( [key=>] value , ... ) // keymay be an integer or string // value maybe any value

A keymay be either an integeror a string. If a key is the standardrepresentation of an integer, it will be interpreted as such (i.e. "8"will beinterpreted as 8, while "08"will be interpreted as "08"). Floats in keyaretruncated to integer. There are no different indexed and associative arraytypes in PHP; there is only one array type, which can both contain integerand string indices.

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Arrays

A value can be of any PHP type.

If you do not specify a key for a given value, then the maximum of the integerindices is taken, and the new key will be that maximum value + 1. If you specify akey that already has a value assigned to it, that value will be overwritten.

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Arrays

Creating/modifying with square-bracket syntax

You can also modify an existing array by explicitly setting values in it.

This is done by assigning values to the array while specifying the key in brackets. You can also omitthe key, add an empty pair of brackets ("[]") to the variable name in that case. $arr[key] = value;$arr[] = value; // keymay be an integer or string // value may be any valueIf$arrdoesn't exist yet,it will be created. So this is also an alternative way to specify an array. To change a certain value,just assign a new value to an element specified with its key. If you want to remove a key/value pair,you need to unset() it.

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ArraysNote that the maximum integer key used for this need not currently exist in the array. It simply must have

existed in the array at some time since the last time the array was re-indexed. The following example

illustrates:

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Arrays

Output:

Array

(

[0] => 1

[1] => 2

[2] => 3

[3] => 4

[4] => 5

)

Array ( )

Array

(

[5] => 6)

Array

(

[0] => 6

[1] => 7

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Exercise

Create two (2) arrays First Array:

Contains letters from A-J

Second Array:

Contains numbers from 1-10 The result must be a third array containing the values

of the first and second array alternatively starting withthe first array value

Example: $arr1 = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} $arr2 = {A, B, C, D, E, F, G, H, I, J}

$arr3 = {1, A, 2, B, 3, C, 4, D, 5, E, 6, F, 7, G, 8, H, 9, I, 10, J}

$arr 3 is the result

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Date and Time

format character Description Example returned valuesDay --- ---

dDay of the month, 2 digits with

leading zeros01 to 31

DA textual representation of a day,

three lettersMon through Sun

Day of the month without leading

zeros1 to 31

l (lowercase 'L')A full textual representation of

the day of the weekSunday through Saturday

N

ISO-8601 numeric representation

of the day of the week (added in

PHP 5.1.0)

1 (for Monday) through 7(for

Sunday)

SEnglish ordinal suffix for the day

of the month, 2 charactersst, nd, rdor th. Works well withj

wNumeric representation of the

day of the week

0 (for Sunday) through 6(for

Saturday)

z The day of the year (startingfrom 0)

0 through 365 27


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Date and Time

format character Description Example returned values

Week --- ---

W

ISO-8601 week number of year,

weeks starting on Monday (added in

PHP 4.1.0)

Example: 42 (the 42nd week in the

year)

Month --- ---

FA full textual representation of a

month, such as January or MarchJanuary throughDecember

mNumeric representation of a month,

with leading zeros01 through 12

MA short textual representation of a

month, three lettersJan throughDec

nNumeric representation of a month,

without leading zeros1 through 12

t Number of days in the given month 28 through 31 28


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Date and Time


Year --- ---

L Whether it's a leap year 1 if it is a leap year, 0 otherwise.

o

ISO-8601 year number. This has

the same value as Y, except that

if the ISO week number (W)

belongs to the previous or next

year, that year is used instead.

(added in PHP 5.1.0)

Examples: 1999 or 2003

YA full numeric representation of

a year, 4 digitsExamples: 1999 or 2003

y

A two digit representation of a

year Examples: 99 or 03 29


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Date and Time


Time --- ---

aLowercase Ante meridiem and

Post meridiemam orpm

AUppercase Ante meridiem and

Post meridiem

AMor PM

B Swatch Internet time 000 through 999

g12-hour format of an hour


G24-hour format of an hour


h12-hour format of an hour with

leading zeros01 through 12

H24-hour format of an hour with

leading zeros00 through 23

i Minutes with leading zeros 00 to 59

s Seconds, with leading zeros 00 through 59 30


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Date and Timeformat character Description Example returned values

Timezone --- ---

eTimezone identifier (added in

PHP 5.1.0)

Examples: UTC, GMT,

Atlantic/Azores

I(capital i)Whether or not the date is in

daylight saving time

1 if Daylight Saving Time, 0

otherwise.

O Difference to Greenwich time(GMT) in hours

Example: +0200

P

Difference to Greenwich time

(GMT) with colon between hours

and minutes (added in PHP 5.1.3)

Example: +02:00

T Timezone setting of this machineExamples:EST,MDT...

Z

Timezone offset in seconds. The

offset for timezones west of UTC

is always negative, and for those

east of UTC is always positive.

-43200 through 43200

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Date and Time


Full Date/Time --- ---

cISO 8601 date (added in PHP

5)2004-02-12T15:19:21+00:00

r RFC 2822 formatted dateExample: Thu, 21 Dec 2000

16:01:07 +0200

U

Seconds since the Unix

Epoch (January 1 1970

00:00:00 GMT)

See also time()

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http://www.faqs.org/rfcs/rfc2822http://c/Users/MythterNote/Desktop/function.time.htmlhttp://c/Users/MythterNote/Desktop/function.time.htmlhttp://www.faqs.org/rfcs/rfc2822


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Exercise

Produce the following formats:

Today is Sunday, July 26, 2009

Today is the 26th day of July, 2009

July 26, 2009 02:00:00 PM 26 July 2009 02:00 pm

26th of July 2009 2:00 PM

07/26/2009 02:00:00 PM

07-26-2009 02:00 pm

20090726-020000PM

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