PHP Date and Time

Question 1

Q: What function is used to get the current timestamp in PHP?

Answer 1

A: time().

Question 2

Q: What does the time() function return?

Answer 2

A: The current Unix timestamp (seconds since January 1, 1970).

Question 3

Q: How do you format a date in PHP?

Answer 3

A: Use the date() function.

Question 4

Q: What is the syntax of the date() function?

Answer 4

A: date(format, timestamp);.

Question 5

Q: What is the default time zone in PHP?

Answer 5

A: It depends on the server configuration, often UTC.

Question 6

Q: How do you format a date as “Year-Month-Day”?

Answer 6

A: date(‘Y-m-d’);.

Question 7

Q: What does the format character d represent in the date() function?

Answer 7

A: Day of the month (01–31).

Question 8

Q: What does the format character m represent in the date() function?

Answer 8

A: Numeric representation of a month (01–12).

Question 9

Q: What does the format character Y represent in the date() function?

Answer 9

A: A four-digit year.

Question 10

Q: What does the format character l represent in the date() function?

Answer 10

A: Full name of the day of the week (e.g., “Monday”).

Question 11

Q: What does the format character H represent?

Answer 11

A: Hour in 24-hour format (00–23).

Question 12

Q: What does the format character h represent?

Answer 12

A: Hour in 12-hour format (01–12).

Question 13

Q: What does the format character i represent?

Answer 13

A: Minutes (00–59).

Question 14

Q: What does the format character s represent?

Answer 14

A: Seconds (00–59).

Question 15

Q: How do you display the current time as HH:MM:SS?

Answer 15

A: date(‘H:i:s’);.

Question 16

Q: How do you set the default time zone in PHP?

Answer 16

A: date_default_timezone_set(‘timezone’);.

Question 17

Q: How do you get the current default time zone?

Answer 17

A: date_default_timezone_get();.

Question 18

Q: How do you list all supported time zones in PHP?

Answer 18

A: Use the timezone_identifiers_list() function.

Question 19

Q: What is the default time zone in a PHP installation if not configured?

Answer 19

A: UTC.

Question 20

Q: How do you format a date for a specific time zone?

Answer 20

A: Use the DateTime class with the setTimezone() method.

Question 21

Q: How do you get the timestamp for a specific date and time?

Answer 21

A: Use the mktime() function.

Question 22

Q: What does the mktime() function return?

Answer 22

A: The Unix timestamp for the specified date and time.

Question 23

Q: What function converts a timestamp into a formatted date?

Answer 23

A: date().

Question 24

Q: How do you convert a formatted date string to a timestamp?

Answer 24

A: Use the strtotime() function.

Question 25

Q: What does the strtotime() function do?

Answer 25

A: Parses a date string into a Unix timestamp.

Question 26

Q: What is the DateTime class in PHP?

Answer 26

A: A class for working with dates and times in an object-oriented way.

Question 27

Q: How do you create a new DateTime object?

Answer 27

A: $date = new DateTime();.

Question 28

Q: How do you format a DateTime object?

Answer 28

A: Use the format() method, e.g., $date->format(‘Y-m-d H:i:s’);.

Question 29

Q: How do you set the time zone for a DateTime object?

Answer 29

A: Use the setTimezone() method.

Question 30

Q: How do you add or subtract time from a DateTime object?

Answer 30

A: Use the add() or sub() method with a DateInterval object.

Question 31

Q: What is the DateInterval class in PHP?

Answer 31

A: A class that represents a time interval.

Question 32

Q: How do you create a DateInterval object?

Answer 32

A: new DateInterval(‘P1D’); (adds one day).

Question 33

Q: What does the P in DateInterval mean?

Answer 33

A: Period; used to define the duration.

Question 34

Q: How do you add one month to a date?

Answer 34

$date->add(new DateInterval(‘P1M’));

Question 35

Q: Can you use negative intervals with DateInterval?

Answer 35

A: Yes, by prefixing with a -, e.g., P-1D.

Question 36

Q: How do you calculate the difference between two dates?

Answer 36

A: Use the diff() method of the DateTime class.

Question 37

Q: What does the diff() method return?

Answer 37

A: A DateInterval object.

Question 38

Q: How do you get the difference in days between two dates?

Answer 38

A: $diff->days.

Question 39

Q: How do you check if a date is in the past?

Answer 39

A: Compare the timestamp with time().

Question 40

Q: How do you determine if a year is a leap year in PHP?

Answer 40

A: Check if date(‘L’, strtotime(‘YYYY-01-01’)) returns 1.