I've seen a code on a project and would like to know how to write a code with less statements.
Here is the code:
if not self.test_done:
phase = "Test"
else:
if self.need_video and not self.video_sent:
phase = 'Video'
else:
if not self.screening1_made and not self.screening2_made:
phase = 'Screening 1'
else:
if ( self.screening1_made and not self.screening2_made ) or not self.passed_screening:
phase = 'Screening 2'
else:
if not self.passed_phase1:
phase = 'Interview 1'
else:
if not self.passed_phase2:
phase = 'Interview 2'
else:
if not self.passed_phase3:
phase = 'Interview 3'
else:
if not self.got_offer:
phase = 'Waiting offer decision'
else:
if self.accepted_offer is None:
phase = 'Waiting decision from candidate'
elif self.accepted_offer == "Accepted":
phase = 'Accepted offer'
elif self.accepted_offer == "Declined":
phase = 'Declined offer'
What would be best practices to avoid nested if statements?
CodePudding user response：
You can extract it to the method and early return, also you can use a dictionary lookup to get your output.
OFFER = {
None: "Waiting decision from candidate",
"Accepted": "Accepted offer",
"Declined": "Declined offer",
}
def some_function_name(self):
if not self.test_done:
return "Test"
if self.need_video and not self.video_sent:
return "Video"
if not self.screening1_made and not self.screening2_made:
return "Screening 1"
if (self.screening1_made and not self.screening2_made) or not self.passed_screening:
return "Screening 2"
if not self.passed_phase1:
return "Interview 1"
if not self.passed_phase2:
return "Interview 2"
if not self.passed_phase3:
return "Interview 3"
if not self.got_offer:
return "Waiting offer decision"
return OFFER.get(self.accepted_offer, None)
CodePudding user response：
This smells to me like a state machine. A "switch - case" construct is often used when evaluating state machines, and while python doesn't currently have that exact feature yet (3.10 will introduce match: case), A list of elif's should do the trick just fine:
if not self.test_done:
phase = "Test"
elif self.need_video and not self.video_sent:
phase = 'Video'
elif self.need_video and not self.video_sent:
phase = 'Video'
elif not self.screening1_made and not self.screening2_made:
phase = 'Screening 1'
elif ( self.screening1_made and not self.screening2_made ) or not self.passed_screening:
phase = 'Screening 2'
elif not self.passed_phase1:
phase = 'Interview 1'
elif not self.passed_phase2:
phase = 'Interview 2'
elif not self.passed_phase3:
phase = 'Interview 3'
elif not self.got_offer:
phase = 'Waiting offer decision'
elif self.accepted_offer is None:
phase = 'Waiting decision from candidate'
elif self.accepted_offer == "Accepted":
phase = 'Accepted offer'
elif self.accepted_offer == "Declined":
phase = 'Declined offer
flattened it's not so bad to look at, and you probably won't find a significantly more elegant solution without changing how you track all the conditionals.
CodePudding user response：
You can use lambda to run expressions. In the example below, we itterate through the list of tuples, containing lambda expressions and strings. When we find a lambda expression that is true, we break out of the loop.
x = 1
expressions = [
(lambda: x == 0, 'X is equal to 0'),
(lambda: x == 1, 'X is equal to 1'),
(lambda: x == 2, 'X is equal to 2'),
]
phrase = 'No result found'
for item in expressions:
expression = item[0]
text = item[1]
if expression():
phrase = text
break
print(phrase)
This is the result.
X is equal to 1
CodePudding user response：
You should refactor your program. Here's a rough Interview class and related objects, which includes a basic dictionary for event names and number of rounds.
class InterviewEvent:
def __init__(self, event_id, event_name, total_rounds) -> None:
self.event_id: int = event_id
self.event_name: str = event_name
self.total_rounds: int = total_rounds
self.competed_rounds: int = 0
self.completed: bool = False
class Interview:
"""Interview class to track interview progress.
"""
def __init__(self, expected_workflow: dict = None):
self.events = []
self.current_event: InterviewEvent = None
if expected_workflow:
self.__init_events(expected_workflow)
def __init_events(self, wf: dict) -> None:
"""Populate events list from workflow dictionary."""
self.events = [InterviewEvent(i, k, v) for i, (k, v) in enumerate(wf.items())]
# Set current event
self.current_event = self.events[0]
def completed_event_round(self, title, round_number):
"""Update round number for event. If complete, increment
to next round or next event in workflow.
"""
for event in self.events:
if event.event_name.lower() == title.lower():
if event.competed_rounds < round_number:
event.competed_rounds = round_number
# Mark event completed if completed rounds equals total rounds.
if event.competed_rounds == event.total_rounds:
event.completed = True
if event.completed:
# Increment current event by 1.
self.current_event = self.events[event.event_id 1]
def __event_attrs(self, e: InterviewEvent) -> str:
return "\n".join([f"{k}: {v}" for k, v in e.__dict__.items()])
@property
def view_current(self):
print(self.__event_attrs(self.current_event))
@property
def remaining_events(self):
return [e for e in self.events if not e.completed]
@property
def view_remaining_events(self):
events_remaining = self.remaining_events
if events_remaining:
print("\n\n".join([self.__event_attrs(e) for e in events_remaining]))
@property
def event_ids(self):
"""Return all current event IDs."""
return [e.event_id for e in self.events]
@property
def event_names(self):
"""Return all current event names."""
return [e.event_name for e in self.events]
# Dictionary of event names and number of rounds.
workflow_rounds = dict(
Test = 1,
Video = 1,
Screening = 2,
Interview = 3,
)
View events that are not complete.
interview.view_remaining_events
Output:
event_id: 0
event_name: Test
total_rounds: 1
competed_rounds: 0
completed: False
event_id: 1
event_name: Video
total_rounds: 1
competed_rounds: 0
completed: False
event_id: 2
event_name: Screening
total_rounds: 2
competed_rounds: 0
completed: False
event_id: 3
event_name: Interview
total_rounds: 3
competed_rounds: 0
completed: False
View current event
interview.view_current
Output:
event_id: 0
event_name: Test
total_rounds: 1
competed_rounds: 0
completed: False
Mark first Test round as complete
interview.completed_event_round(title = "Test", round_number = 1)
Again, view events that are not complete.
interview.view_remaining_events
Output:
event_id: 1
event_name: Video
total_rounds: 1
competed_rounds: 0
completed: False
event_id: 2
event_name: Screening
total_rounds: 2
competed_rounds: 0
completed: False
event_id: 3
event_name: Interview
total_rounds: 3
competed_rounds: 0
completed: False
Finally, view current event
interview.view_current
Output:
event_id: 1
event_name: Video
total_rounds: 1
competed_rounds: 0
completed: False