Basic PHP Constructs

Lecture on using basic PHP construct

Transcript

1. Basic constructs in PHP Chencha Jacob 1
2. Months of the year Months of the year Our goal today is to generate this output January - 31 days February - 28 days March - 31 days April - 30 days May - 31 days June - 30 days July - 31 days August - 31 days September - 30 days October - 31 days November - 30 days December - 31 days That is the number of days in a month for the current year. 2
3. Loop to generate generic date each month Loop to generate generic date each month <?php $months= ["January","February","March","April","May","June", "July","August","September","October","November","December"]; foreach ($months as $month) { $firstDateInMonth="1st " . "{$month} " . date("Y"); echo $firstDateInMonth; } 3
4. Generating days of the month Generating days of the month <?php $months= ["January","February","March","April","May","June", "July","August","September","October","November","December"]; foreach ($months as $month) { $firstDateInMonth="1st " . "{$month} " . date("Y"); $dayAsTimeStamp=strtotime($firstDateInMonth); $dayInMonth=date("t",$dayAsTimeStamp); echo $dayInMonth; } 4
5. Formatting the date Formatting the date <?php $months= ["January","February","March","April","May","June", "July","August","September","October","November","December"]; foreach ($months as $month) { $firstDateInMonth="1st " . "{$month} " . date("Y"); $dayAsTimeStamp=strtotime($firstDateInMonth); $dayInMonth=date("t",$dayAsTimeStamp); echo "{$month} - {$dayInMonth} </br>"; } 5
6. Reusing Code Reusing Code Our code so far works and gives the desired output. However suppose we wanted to know the number of days in a month given the month? 6
7. Roping in functions Roping in functions <?php $months= ["January","February","March","April","May","June", "July","August","September","October","November","December"]; foreach ($months as $month) { $dayInMonth=daysOfMonth($month); echo "{$month} - {$dayInMonth} </br>"; } function daysOfMonth($month){ $firstDateInMonth="1st " . "{$month} " . date("Y"); $dayAsTimeStamp=strtotime($firstDateInMonth); $dayInMonth=date("t",$dayAsTimeStamp); return $dayInMonth; } Now we have neatly packed this bit of logic into a function that we can use another day. As an exercise, try think of how you could make the exercise more robust. 7
8. Sample Usage Sample Usage <?php $month=$_REQUEST["month"]; $dayInMonth=daysOfMonth($month); echo "This month has $dayInMonth"; function daysOfMonth($month){ $firstDateInMonth="1st " . "{$month} " . date("Y"); $dayAsTimeStamp=strtotime($firstDateInMonth); $dayInMonth=date("t",$dayAsTimeStamp); return $dayInMonth; } 8
9. End of month pains End of month pains Now let us suppose that we get broke on 29th and salary checks in on 1st. Then for days with 31 days we would be in a sorry state. We would like to have a system that prints out status of our wallet. Something like January - Broke February - Good March - Broke April - Good May - Broke June - Good July - Broke August - Broke September - Good October - Broke November - Good December - Broke How do you suppose we would impliment something of this sort? 9
10. Teaching your computer to decide Teaching your computer to decide <?php $months= ["January","February","March","April","May","June", "July","August","September","October","November","December"]; foreach ($months as $month) { $dayInMonth=daysOfMonth($month); if($dayInMonth > 30){ echo "{$month} - Broke </br>"; } else { echo "{$month} - Good </br>"; } } function daysOfMonth($month){ $firstDateInMonth="1st " . "{$month} " . date("Y"); $dayAsTimeStamp=strtotime($firstDateInMonth); $dayInMonth=date("t",$dayAsTimeStamp); return $dayInMonth; } 10
11. Assignment Assignment Write a PHP script that shows the day of the week for the last day of the month. Eg January first day was Thursday February first day was Sunday etc 11