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)

• Teepeemm: But what does your code do? The standard on this site is to make that the title. And explain that a bit in the body. See How to Ask and help center.
• FMc: This code is incomplete (and won't run) without an except block.
• JThao: Ahh sorry missed it on copy paste
• Reinderien: My answer missed the fact that you're using Python 2 so I'll update it. But why are you doing so?

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()

• JThao: I'm using Python 2, in def str how would the format work?
• Reinderien: @JThao don't use Python 2.
• JThao: I get that a lot but I don't have a choice in this matter :(
• Reinderien: @JThao Edited; minor changes necessary.
• Reinderien: First, if your class has 50 more fields/attributes, it's possible that that's needed and appropriate, but also possible that that's a data schema misrepresentation and/or a normalisation error. Impossible to say without seeing it.