1
00:00:00,000 --> 00:00:06,576
So we've got our time, date or
datetime objects, what now?

2
00:00:06,576 --> 00:00:09,725
When we print out, let's say,

3
00:00:09,725 --> 00:00:15,218
a datetime we get a string in
the default Python format.

4
00:00:15,218 --> 00:00:19,503
But what if we want to format
this date a certain way?

5
00:00:19,503 --> 00:00:26,683
Perhaps the American month-day-year or
the Australian day-month-year.

6
00:00:26,683 --> 00:00:32,907
We might want our date as a number and
the month as a word like August 8.

7
00:00:32,907 --> 00:00:37,336
Or maybe we want all numbers
to be zero-padded and

8
00:00:37,336 --> 00:00:41,035
separated with a slash like 01/02.

9
00:00:41,035 --> 00:00:45,913
Well, datetime comes with methods
to help us with formatting and

10
00:00:45,913 --> 00:00:49,125
parsing our datetime objects.

11
00:00:49,125 --> 00:00:56,670
First, we have stringftime() or
String Format Time.

12
00:00:56,670 --> 00:01:02,773
This is a method that is available
to time, date and datetime objects.

13
00:01:02,773 --> 00:01:06,290
This method converts an instance of one of

14
00:01:06,290 --> 00:01:10,920
these objects to a string
according to a given format.

15
00:01:10,920 --> 00:01:17,540
This means you'll need to call it on
an object that we have already created.

16
00:01:17,540 --> 00:01:24,502
The syntax looks like this
object.strftime(format)

17
00:01:24,502 --> 00:01:29,287
where format tells Python how we want to

18
00:01:29,287 --> 00:01:33,790
format our time, date or datetime.

19
00:01:33,790 --> 00:01:40,691
In the teacher's notes, you'll find a link
to Python's documentation on format codes.

20
00:01:40,691 --> 00:01:45,653
Each of these directives,
a percentage sign plus a letter,

21
00:01:45,653 --> 00:01:50,530
represents a certain element in a date,
time or datetime.

22
00:01:50,530 --> 00:01:55,788
For example,
it says here that %H is a zero-padded

23
00:01:55,788 --> 00:02:02,610
number from 0 to 23 that represents
the hour on a 24 hour clock.

24
00:02:02,610 --> 00:02:05,480
Let's see these in action.

25
00:02:05,480 --> 00:02:07,755
First, let's create some objects.

26
00:02:07,755 --> 00:02:13,738
t = datetime.time(hour = 11,

27
00:02:13,738 --> 00:02:16,440
minute = 3),

28
00:02:16,440 --> 00:02:22,809
d = datetime.date(2023, 8,

29
00:02:22,809 --> 00:02:32,460
16) and
dt = datetime.datetime.combine (d, t).

30
00:02:32,460 --> 00:02:36,011
Now, let's see strftime in action.

31
00:02:36,011 --> 00:02:42,696
t.strftime("%H:%M") will

32
00:02:42,696 --> 00:02:46,579
give us 11:03.

33
00:02:46,579 --> 00:02:53,929
d.strftime("%a %d/%m/%Y")

34
00:02:53,929 --> 00:03:02,543
will give us Wednesday 16/08/2023.

35
00:03:02,543 --> 00:03:07,424
And dt.strftime("%M

36
00:03:07,424 --> 00:03:12,302
minutes past %I %p on %B

37
00:03:12,302 --> 00:03:18,512
%d") will give us 03 minutes

38
00:03:18,512 --> 00:03:23,849
past 11 AM on August 16.

39
00:03:23,849 --> 00:03:28,737
Using this reference,
you can piece together all sorts

40
00:03:28,737 --> 00:03:33,529
of formats for your time,
date and datetime objects.

41
00:03:33,529 --> 00:03:38,405
You may also come across other
format code lists in your

42
00:03:38,405 --> 00:03:42,017
Python journey such as strftime.org.

43
00:03:42,017 --> 00:03:49,710
My only warning is this, some lists offer
format codes that are platform specific.

44
00:03:49,710 --> 00:03:54,281
This means that this format
code might only work for

45
00:03:54,281 --> 00:03:57,478
MacOS or Windows and not the other.

46
00:03:57,478 --> 00:04:02,463
Remember, when we're creating apps for
clients or users one day,

47
00:04:02,463 --> 00:04:07,370
we must be as neutral as possible
in terms of the operating system.

48
00:04:07,370 --> 00:04:11,695
My recommendation is to
avoid using these platform

49
00:04:11,695 --> 00:04:15,119
specific format codes where possible.

50
00:04:15,119 --> 00:04:22,910
Next, we have datetime.strptime() or
string parse time.

51
00:04:22,910 --> 00:04:27,288
This method does
the opposite of strftime().

52
00:04:27,288 --> 00:04:33,970
It parses a string into a datetime
object according to a given format.

53
00:04:33,970 --> 00:04:39,329
Now this is only available
in the datetime class.

54
00:04:39,329 --> 00:04:48,493
The syntax looks like this
datetime.strptime(datestr, format).

55
00:04:48,493 --> 00:04:53,439
datestr is simply a string with
our datetime information that

56
00:04:53,439 --> 00:04:56,680
we want to parse into a datetime object.

57
00:04:56,680 --> 00:05:02,350
For example, 27 September 2022 or

58
00:05:02,350 --> 00:05:07,859
16:00 16/08/2023.

59
00:05:07,859 --> 00:05:12,759
Then, we're already familiar
with format. This section uses

60
00:05:12,759 --> 00:05:14,920
a string of format codes

61
00:05:14,920 --> 00:05:20,920
so Python can match up our date
string to what each section means.

62
00:05:20,920 --> 00:05:23,219
Let's try it out.

63
00:05:23,219 --> 00:05:27,923
Make sure we've imported datetime,

64
00:05:27,923 --> 00:05:36,866
datetime.datetime.strptime("27 September
2022",

65
00:05:36,866 --> 00:05:43,467
%d ,%B ,%Y") and that gives us a datetime.

66
00:05:43,467 --> 00:05:46,199
Let's try it again

67
00:05:46,199 --> 00:05:54,401
with datetime.datetime.strptime(''16:00

68
00:05:54,401 --> 00:05:59,012
16/08/2023", And

69
00:05:59,012 --> 00:06:05,171
the format is %H:%M %d/%m/%Y")

70
00:06:06,651 --> 00:06:11,241
And there we have it,
another datetime with all of the correct

71
00:06:11,241 --> 00:06:14,519
information that we had
in our date string.

72
00:06:14,519 --> 00:06:20,400
String parse time is usually used
when we have to parse user input.

73
00:06:20,400 --> 00:06:24,527
For example,
when an app asks user to let's say,

74
00:06:24,527 --> 00:06:28,373
enter their birthday, or
an events start time,

75
00:06:28,373 --> 00:06:33,280
we then convert this into an object
that we can use, a date time.