describe

Read two time data (data format for example: 2019.01.01, data type is string) from the json file, and calculate the result, and print out the number of days between the two times.

I / O description

Input description

The JSON file name is datetime.json. The format is as follows:

{
  "day1": "1949.10.01",
  "day2": "2019.04.25"
}

Output description

How many days did the console print between the two times (day1 and day2).

25408

Solutions

After reading the data in the json file, parse the useful parts and check (check whether the format is correct). When the date format is correct, convert the date to datetime.date and calculate it. Finally output the result.

Code

"""
//Time difference calculation.
//Read two time data from the json file, calculate and print how many days between the two times.
"""

import datetime
import json
import traceback

class TimeFormatError(Exception):
    def __init__(self, message):
        self.message = "TimeFormatError: " + message


def days_compute(times):
    """
    Calculated date interval.
    :param times: <dict> time dictionary
    :return: <int> date interval
    """
    time1 = times["day1"]
    time2 = times["day2"]

    if time1.count(".") < 2:
        raise TimeFormatError("Time format(yyyy.mm.dd) error. %s" % time1)
    if time2.count(".") < 2:
        raise TimeFormatError("Time format(yyyy.mm.dd) error. %s" % time2)

    date1 = parse(time1)
    date2 = parse(time2)

    return (date2 - date1).days


def parse(time_str):
    """
    Parse time format.
    :param time_str: <str> time string
    :return: <datetime.date> date
    """
    time_list = time_str.split(".")
    year = time_list[0]
    month = time_list[1]
    day = time_list[2]

    return datetime.date(int(year), int(month), int(day))


def read_json_file(path):
    """
    Read json file.
    :param path: <str> json file url
    :return: <dict> json file data
    """
    with open(path, "r") as json_file:
        data = json.load(json_file)
    json_file.close()

    return data


# main method
url = "datetimes.json"

try:
    base = read_json_file(url)
    day = days_compute(base)
    print(day)
except TimeFormatError as e:
    print(str(e))
    print("errmsg:\n%s" % traceback.format_exc())
except Exception as e:
    print(str(e))
    print("errmsg:\n%s" % traceback.format_exc())

Code review

import datetime
import json
import traceback

# Custom exception type timeformatererror, used to throw when verifying the error time format in the code
class TimeFormatError(Exception):
    def __init__(self, message):
        self.message = "TimeFormatError: " + message


# Define a function to calculate the date difference
def days_compute(times):
    """
    Calculated date interval.
    :param times: <dict> time dictionary
    :return: <int> date interval
    """
    
    # Get two time dates from the dictionary
    time1 = times["day1"]
    time2 = times["day2"]

    # Check the date format. If the date format is wrong (for example, "2019.10"), throw timeformatererror
    if time1.count(".") < 2:
        raise TimeFormatError("Time format(yyyy.mm.dd) error. %s" % time1)
    if time2.count(".") < 2:
        raise TimeFormatError("Time format(yyyy.mm.dd) error. %s" % time2)

    # Call the custom parse function here to convert the two date time formats from string to datetime.date format
    date1 = parse(time1)
    date2 = parse(time2)

    # Return calculation result (integer)
    return (date2 - date1).days


# Parse time string, convert to datetime.date format
def parse(time_str):
    """
    Parse time format.
    :param time_str: <str> time string
    :return: <datetime.date> date
    """
    # Use the split() function to convert the string into a list and decompose the date
    time_list = time_str.split(".")
    year = time_list[0]
    month = time_list[1]
    day = time_list[2]

    # Convert date to datetime.date format and return
    return datetime.date(int(year), int(month), int(day))


# Read the information of json file and convert it to dictionary format
def read_json_file(path):
    """
    Read json file.
    :param path: <str> json file url
    :return: <dict> json file data
    """
    with open(path, "r") as json_file:
        data = json.load(json_file)
    json_file.close()

    return data


# main method
# Where the code starts executing
# The url of the json file
url = "datetimes.json"

try:
    # Call the custom read json file function to get the contents of the json file
    base = read_json_file(url)

    # Calculate the result and print it out
    day = days_compute(base)
    print(day)

# Catch exceptions, print error messages and stacks
except TimeFormatError as e:
    print(str(e))
    print("errmsg:\n%s" % traceback.format_exc())
except Exception as e:
    print(str(e))
    print("errmsg:\n%s" % traceback.format_exc())