Function to add a new key pair value to my JSON file

Question

As you can see I am using a counter variable to iterate through my JSON file and it's a dictionary that has a list of dictionaries. Once I find the key normalHours I divide it and add it to my dictionary hours_per_week. Then I update the dictionary it is associated with. Is it better to use for i in range instead of the counter? Anything else I can do to clean up or speed up the code?

Here is my json file, I deleted most of the key pairs for easier readability.

{ "employeeData": [ { "normalHours": 80, "givenName": "ROBERTO", }, { "normalHours": 80, "givenName": "HEATHER", }, { "normalHours": 80, "givenName": "PAUL", } ] }

def add_hours_per_week(json_file):
    """
    Add new dictionary value hoursPerWeek to our JSON data
    """
    # Create new dictionary hours_per_week.
    hours_per_week = {}
    hours_divide_by_2 = 0
    normal_hours_counter = 0

    try:
        for key, values in json_file.items():
            if str(key) == "employeeData":
                # JSON is in a list of dictionaries
                for item in values:
                    # If normalHours field is Null, "", or 0 add an empty field
                    if not item["normalHours"] or item["normalHours"] == 0:
                        hours_per_week["hoursPerWeek"] = ""
                    else:
                        # Divide normalHours by 2 rounded to 2 decimals.
                        hours_divide_by_2 = round(float(item["normalHours"]) / 2, 2)
                        hours_per_week["hoursPerWeek"] = hours_divide_by_2
                    json_file['employeeData'][normal_hours_counter].update(hours_per_week)
                    normal_hours_counter += 1
        print("%d employee updated with hoursPerWeek" % normal_hours_counter if normal_hours_counter <= 1 else
              "%d employees updated with hoursPerWeek" % normal_hours_counter)
        return json_file

    except Exception as e:
        print("Exception in add_hours_per_week: ", e)

Answer 1

This code exhibits a collection of anti-patterns typically seen in Python that together are making your life more difficult:

• Dictionary lasagna, having non-structured data used directly from the result of a JSON parse
• In-place mutation
• Exception swallowing
• Infectious nullity

I don't see any value in your employees updated print. At the absolute least, this should be converted to a proper logging call, but I would sooner drop it entirely.

This code needs to be significantly re-thought, along with any code you haven't shown that depends on such patterns. Consider instead:

• Define a simple dataclass or NamedTuple representing each Employee
• Write a simple property method for hours_per_week
• Do not round() in your business logic, only upon presentation
• Explicit casting to a float should not be needed

Suggested

from typing import Any, Iterable, Iterator, NamedTuple, Optional


class Employee(NamedTuple):
    given_name: str
    normal_hours: Optional[float]

    @classmethod
    def from_dict(cls, data: Iterable[dict[str, Any]]) -> Iterator['Employee']:
        for employee in data:
            yield cls(
                given_name=employee['givenName'],
                normal_hours=employee.get('normalHours'),
            )

    @property
    def hours_per_week(self) -> Optional[float]:
        return self.normal_hours and self.normal_hours / 2

    def __str__(self) -> str:
        if self.normal_hours:
            return (
                f'{self.given_name}:'
                f' {self.normal_hours} hours,'
                f' {self.hours_per_week:.2f} hours per week'
            )
        return self.given_name


def main() -> None:
    json_content = {
        'employeeData': [
            {'normalHours':   80, 'givenName': 'ROBERTO'},
            {'normalHours':   80, 'givenName': 'HEATHER'},
            {'normalHours':   80, 'givenName': 'PAUL'},
            {'normalHours': None, 'givenName': 'JULIO'}
        ]
    }
    employees = Employee.from_dict(json_content['employeeData'])

    for employee in employees:
        print(employee)


if __name__ == '__main__':
    main()

Output

ROBERTO: 80 hours, 40.00 hours per week
HEATHER: 80 hours, 40.00 hours per week
PAUL: 80 hours, 40.00 hours per week
JULIO

Python 2

Similar, just worse.

class Employee:
    def __init__(self, given_name, normal_hours):
        self.given_name = given_name
        self.normal_hours = normal_hours

    @classmethod
    def from_dict(cls, data):
        for employee in data:
            yield cls(
                given_name=employee['givenName'],
                normal_hours=employee.get('normalHours'),
            )

    @property
    def hours_per_week(self):
        return self.normal_hours and self.normal_hours / 2

    def __str__(self):
        if self.normal_hours:
            return '%s: %f hours, %.2f hours per week' % (
                self.given_name,
                self.normal_hours,
                self.hours_per_week,
            )
        return self.given_name


def main():
    json_content = {
        'employeeData': [
            {'normalHours':   80, 'givenName': 'ROBERTO'},
            {'normalHours':   80, 'givenName': 'HEATHER'},
            {'normalHours':   80, 'givenName': 'PAUL'},
            {'normalHours': None, 'givenName': 'JULIO'}
        ]
    }
    employees = Employee.from_dict(json_content['employeeData'])

    for employee in employees:
        print(employee)


if __name__ == '__main__':
    main()