Monday, April 21, 2008

Conditional Statements if...else in PHP

Look at the following code:

  $t=(int) date("G");

    echo "Good Morning!";
  else if($t<17)
    echo "Good Afternoon!";
  else if($t<21)
    echo "Good Evening!";
    echo "Good Night!";

If you are a reader of this blog (or know C++!) then the code would look familiar.

As is obvious, that is a PHP code but looks similar to C++.

You see, the if and else statements are all similar to that in C++.

Talking about the code, it is pretty straightforward, we are taking the current time, type casting it to an integer in a variable $t (type casting is also done in the similar manner in C++). Then we are printing different messages according to what the current time is.

That being clear, let’s us look at the working of date() function a bit. We’ve previously used date function in the post Writing and Running PHP Scripts. As I explained, it takes a string as an argument through which we can tell the function to return the date/time in the format we want.

Previously, we used date function with the format string "h:i A, jS F Y" and in this post we are using “G”. Actually each character in the string we send as an argument represent one part of date/time. PHP’s date function understands more that 30 different characters which can be used to get the time in the required format.

Taking the example of the format string "h:i A, jS F Y". we have h,:,I,A,j,S,F,Y characters in it which means the following:

  • h-Hour of the day in 12-hour format with leading zeros. Range: 01 to 12.
  • i-Minutes past, with leading zeros. Range: 00 to 59.
  • A-Morning or afternoon, in UPPER case letters. Maybe AM or PM.
  • j-Day of the month without leading zeros. Range: 1 to 31.
  • S-Ordinal suffix for the current date. May be st, nd, rd, th.
  • F-Month of the year in full text format. Range: January to December.
  • Y-Year in 4-digit format.

So on 26th may 2008 at 12:00 PM, using the format string "h:i A, jS F Y", we’ll get

  • “12” from h
  • “:” as it is
  • “00” form i
  • “ “ (space) as it is
  • “PM” from A
  • “, “ as it is
  • “ “ (space) as it is
  • “26” from j
  • “th” from S
  • “ “ (space) as it is
  • “May” from F
  • “ “ (space) as it is
  • “2008” form Y

Combining them it makes

12:00 PM, 26th May 2008

In the code at the top of this post, we sent the format string “G” to the date function which returns the hour of the day in 24-hour format without leading zeros. Since date() function returns a string we type casted it to and integer before storing it in $t, which would ease arithmetic calculations.

Here, we are also using a variable and type casting without much discussion, we’ll discuss them in detail in the coming posts.

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