Iterable vs. Scalar, Pandas Datetime Module

💡 The difference between an iterable and a scalar data type

---

Iterable

• Definition : An object capable of returning its members one at a time
• Example
  • List : Order exists, mutable
  • Tuple : Order exists, immutable
  • String : A set of ordered characters
  • Dictionary : A set of key-value pairs
  • Set : A set of unique elements, unordered
• Characteristics
  • Usable in a for loop
  • Can be passed to functions like len(), sorted(), reversed()
  • Contains single data, not iterable

Scalar

• Definition : Represents a single value, not iterable
• Example
  • Int : Integer
  • Float : A number that includes a decimal point
  • Boolean : True/False
  • NoneType
• Charateristics
  • Not usable in a for loop
  • Represents a single value, used to express basic and atomic data

Example Codes for Error

• Iterable Example

my_list = [1,2,3,4]
for item in my_list:
	print(item)

• Scalar Exmaple (Error)

my_int = 5  
for item in my_int:
	print(item) 
#TypeError: 'int' object is mot iterable

💡 Pandas Datetime Module

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Datetime

• Definition : A module for handling dates and times, providing several classes and methods to perform various tasks such as calculating, formatting, and comparing dates and times.
• Main Classes
  • datetime.datetime : A class that represents both date and time
  • datetime.date : A class that represents only the year, month, and day
  • datetime.time : A class that represents only hours, minutes, seconds, and microseconds.
  • datetime.timedelta : A class that represents the difference between two dates or times.
  • datetime.tzinfo : Abstract based class representing time zone information
• Example Code
  • Get current date and time

    from datetime import datetime
    
    now = datetime.now()
    print("Current Date and Time:", now)

  • Get current date

    from datetime import datetime
    
    today = date.today()
    print("Current Date:", today)

  • Create a specific date and time

    from datetime import datetime
    
    specific_date = datetime(2024, 6, 27, 15, 30)
    print("Specific Date and Time:", specific_date)
    

  • Date Formatting

    from datetime import datetime
    
    now = datetime.now()
    formatted_date = now.strftime("%Y-%m-%d %H:%M:%S")
    print("Formatted Date and Time:", formatted_date)

  • Convert string to date

    from datetime import datetime
    
    date_string = "2024-06-27 15:30:00"
    parsed_date = datetime.strptime(date_string, "%Y-%m-%d %H:%M:%S")
    print("Date converted from String:", parsed_date)

  • Calculate date difference

    from datetime import date
    
    date1 = date(2024, 6, 27)
    date2 = date(2023, 6, 27)
    difference = date1 - date2
    print("Date Difference:", difference.days, "일")

  • Setting time zone (using pytz)

    from datetime import datetime
    import pytz
    
    tz_korea = pytz.timezone('Asia/Seoul')
    now_korea = datetime.now(tz_korea)
    print("Time in Korea:", now_korea)

  • Add time to date

    from datetime import datetime, timedelta
    
    now = datetime.now()
    future_date = now + timedelta(days=10)
    print("Time and Date after 10 days:", future_date)

  • Compare specific times

    from datetime import datetime
    
    time1 = datetime(2024, 6, 27, 15, 30)
    time2 = datetime(2023, 6, 27, 15, 30)
    if time1 > time2:
        print("time1 is later than time2.")
    else:
        print("time1 is before time2.")

  • Find the day of the week

    from datetime import datetime
    			now = datetime.now()
    			weekday = now.weekday()  # 월요일이 0, 일요일이 6
    			days = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
    			print("Today is:", days[weekday])