Date and Time

LESSON

This lesson is a follow up to Unit 2: Strings and Console input and will give you practice with the concepts introduced in that lesson.

설명: [ 학습방향 ]
이 장에서는 2장의 연장선으로, 다양한 문자열을 콘솔에 출력하는 방법을 연습한다.


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DATA AND TIME

1. The datetime Library

A lot of times you want to keep track of when something happened. We can do so in Python using datetime.

Here we’ll use datetime to print the date and time in a nice format.

설명: [ Learn ]
• Ch1. The datetime Library 에서는 datetime 클래스를 학습한다.
• 날짜와 시간을 사용하고자 하면, 클래스 datetime 을 사용한다.


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  • Click Run to continue.

설명: [ Instruction ]
• Run 을 클릭하여 실행하라.


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  • skip

설명: [ Hint ]
• skip


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from datetime import datetime

설명: [ Solution ]
• 클래스 datetime 으로 부터 datetime 을 import 한다.

결과

#skip


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PYTHON SYNTAX

2. Getting the Current Date and Time

We can use a function called datetime.now() to retrieve the current date and time.

from datetime import datetime
print (datetime.now())

The first line imports the datetime library so that we can use it.

The second line will print out the current date and time.

설명: [ Learn ]
• Ch2. Getting the Current Date and Time 에서는 현재시간을 학습한다.
• datetime.now() 는 현재 날짜와 시간을 알려주는 함수이다.
• datetime 을 사용하기 위해서는 클래스 datetime 기본제공 함수를 사용한다.
• datetime.now() 를 출력한다.


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  • Create a variable called now and store the result of datetime.now() in it.

  • Then, print the value of now.

설명: [ Instruction ]
• 변수 now 를 만들어라.
• 변수 now 에 datetime.now() 를 대입하라.
• 변수 now 를 출력하라.


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  • Remember that you can assign a value to the variable now using the assignment operator =

  • For example, if you wanted to store the value 4 in now, you would type:

now = 4

설명: [ Hint ]
• 변수를 대입할때 ( = )를 사용한다.


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from datetime import datetime

now = datetime.now()
print (now)

설명: [ Solution ]
• 클래스 datetime 를 import 한다.
• 변수 now 를 만들고, datetime.now() 를 저장한다.
• datetime.now() 는 현재 일자와 날짜를 반환한다.
• 변수 now 를 출력한다.

결과

2018-11-27 10:27:29.102097


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codecademy

PYTHON SYNTAX

3. Extracting Information

Notice how the output looks like 2013-11-25 23:45:14.317454. What if you don’t want the entire date and time?

from datetime import datetime
now = datetime.now()

current_year = now.year
current_month = now.month
current_day = now.day

You already have the first two lines.

In the third line, we take the year (and only the year) from the variable now and store it in current_year.

In the fourth and fifth lines, we store the month and day from now.

설명: [ Learn ]
• Ch3. Extracting Information 에서는 년, 월, 일을 학습한다.
• 변수 now 에 datetime.now() 저장하라.


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  • On a new line, print now.year.
  • Make sure you do it after setting the now variable!
  • Then, print out now.month.
  • Finally, print out now.day.

설명: [ Instruction ]
• 라인 3 에 다음 3 개를 작성 후 실행하라.
• now.year 을 출력하라.
• now.month 을 출력하라.
• now.day 을 출력하라.


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  • Remember, to print out the current year, you can type:
print (now.year)

설명: [ Hint ]
• 변수 now 에 저장된 year 값을 직접 출력할 수 있다.


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from datetime import datetime
now = datetime.now()

print (now.year)
print (now.month)
print (now.day)

설명: [ Solution ]
• 변수 now 의 ( .year ) , ( .month ) , ( .day )를 출력한다.

결과

2018
11
27


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codecademy

PYTHON SYNTAX

4. Hot Date

What if we want to print today’s date in the following format? mm/dd/yyyy. Let’s use string substitution again!

from datetime import datetime
now = datetime.now()

#Python2
print ('%02d-%02d-%04d' % (now.month, now.day, now.year))

#Python3
d = datetime.today()
print ( '{:%m-%d-%Y}'.format(d) )
print ( datetime.today().strftime('%m-%d-%y') )
print (f'{now.month}-{now.day}-{now.year}')
# will print the current date as mm-dd-yyyy

Remember that the standalone % operator after the string will fill the %02d and %04d placeholders in the string on the left with the numbers and strings in the parentheses on the right.

%02d pads the month and day numbers with zeros to two places, and %04d pads the year to four places. This is one way dates are commonly displayed.

설명: [ Learn ]
• Ch4. Hot Date 에서는 날짜&시간의 출력 형태를 학습한다.
• 변수 now 에 저장된 날짜 & 시간을 예제와 같이 사용하고자 한다.
• e.g. 12-28-2002
• print 문 출력시, 월 : %02d , 일 : %02d , 년 : %04d 로 작성한다.


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  • Print the current date in the form of mm/dd/yyyy.

  • Change the string used above so that it uses a / character in between the %02d and %04d placeholders instead of a - character.

설명: [ Instruction ]
• 날짜를 mm/dd/yyyy 형태로 출력하라.


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  • Don’t forget to import datetime. The example code above shows you how to do so.

  • Make sure you use now.day instead of now.date. They are different things!

설명: [ Hint ]
• import datetime 을 선언하라.
• now.day , now.month , now.year 를 사용하라.


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from datetime import datetime
now = datetime.now()
#Python2
print ('%02d/%02d/%04d' % (now.month, now.day, now.year))
#Python3
d = datetime.today()
print ( '{:%m/%d/%Y}'.format(d) )

설명: [ Solution ]
• 출력을 월, 일, 년도 를 %02d/%02d/%04d 로 표현한다.
• Python3는 {:%m/%d/%Y} 으로 표시한다.

결과

11/27/2018


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codecademy

PYTHON SYNTAX

5. Pretty Time

Nice work! Let’s do the same for the hour, minute, and second.

from datetime import datetime
#Python2
now = datetime.now()

print (now.hour)
print (now.minute)
print (now.second)
#Python3
d = datetime.today()
print ('{:%H}'.format(d))
print ('{:%M}'.format(d))
print ('{:%S}'.format(d))

In the above example, we just printed the current hour, then the current minute, then the current second.

We can again use the variable now to print the time.

설명: [ Learn - Python2 ]
• Ch5. Pretty Time 에서는 시간을 학습한다.
• 변수 now 에 저장 되어 있는 값 중 hour, minute, second 를 각각 출력한다.

설명: [ Learn - Python3 ]
• 변수 d 에 저장 되어 있는 값 중 hour, minute, second 를 각각 출력한다.

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  • Similar to the last exercise, print the current time in the pretty form of hh:mm:ss.

  • Change the string that you are printing so that you have a : character in between the %02d placeholders.

  • Change the three things that you are printing from month, day, and year to now.hour, now.minute, and now.second.

설명: [ Instruction ]
• 시간은 hour, minute, second 를 사용한다.
• 사용 방법은 now.hour , now.minute , now.second 이다.


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  • To get the hour, you can type:
now.hour

You can also use now.minute and now.second.

설명: [ Hint ]
• now.minute , now.second , now.hour 를 사용하라.


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from datetime import datetime
#Python2
now = datetime.now()

print ('%02d:%02d:%02d' % (now.hour, now.minute, now.second))

#Python3
d = datetime.today()
print ('{:%H:%M:%S}'.format(d))

설명: [ Solution ]
• 시, 분, 초 를 %02d:%02d:%02d 형식으로 출력한다.
• 시, 분, 초 를 %H:%M:%S 형식으로 출력한다.

결과

10:52:23


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codecademy

PYTHON SYNTAX

6. Grand Finale

We’ve managed to print the date and time separately in a very pretty fashion. Let’s combine the two!

from datetime import datetime
now = datetime.now()

print ('%02d/%02d/%04d' % (now.month, now.day, now.year))
print ('%02d:%02d:%02d' % (now.hour, now.minute, now.second))

The example above will print out the date, then on a separate line it will print the time.

Let’s print them all on the same line in a single print statement!

설명: [ Learn ]
• Ch6. Grand Finale 에서는 datetime 사용법을 학습한다.
• 날짜를 반환하는 date 와 시간을 반환하는 time 사용법을 학습한다.


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  • Print the date and time together in the form: mm/dd/yyyy hh:mm:ss.
  • To start, change the format string to the left of the % operator.
  • Ensure that it has five %02d and one %04d placeholder.
  • Put slashes and colons and a space between the placeholders so that they fit the format above.Then, change the variables in the parentheses to the right of the % operator.
  • Place the variables so that now.month, now.day, now.year are before now.hour, now.minute, now.second. Make sure that there is a ( before the six placeholders and a ) after them.

설명: [ Instruction ]
• day/month/year hour:minute:second 형식으로 출력하라.


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  • Don’t forget to import datetime. Look at the example code above if you need help doing so.

설명: [ Hint ]
• import datetime 를 사용하라.


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from datetime import datetime
#Python2
now = datetime.now()

print ('%02d/%02d/%04d %02d:%02d:%02d' % (now.month, now.day, now.year, now.hour, now.minute, now.second))

#Python3
d = datetime.today()
print ('{:%m/%d/%Y %H:%M:%S}'.format(d))

설명: [ Solution ]
• Print 문의 %s 을 기능을 사용하여, 각 변수의 값을 대입한다.

결과

11/27/2018 20:59:59