7 Suggestions for Naming python Variables

Preface

According to the voting statistics of one developer in Quora Q&A community, the biggest problem for programmers is how to name (for example, give variables, classes, functions, etc.). The votes for one item alone are almost the sum of the voting results of the other eight items. How to name a variable and how to make it meaningful has become an insurmountable problem for programmers. This article refers to Clean Code and provides 7 naming suggestions, hoping to bring you some help in the process of naming.

The following are based on Python 3.7 syntax

1. Use meaningful and readable variable names

Difference

ymdstr = datetime.date.today().strftime("%y-%m-%d")

Who knows what ymd is?

Good

current_date: str = datetime.date.today().strftime("%y-%m-%d")

When you see current_date, you can understand it with one eye.

2. Use the same vocabulary for variables of the same type

These three functions are all user-related information, but they use three names

get_user_info()
get_client_data()
get_customer_record()

Ok, if the entities are the same, you should unify 1 name

get_user_info()
get_user_data()
get_user_record()

Excellent because Python is an object-oriented language, it is more reasonable to use a class to realize it, which is represented by instance attributes, property methods and instance methods respectively.

class User:
  info : str

  @property
  def data(self) -> dict:
    # ...

  def get_record(self) -> Union[Record, None]:
    # ...

3. Use searchable names

Most of the time you are reading code instead of writing code, so it is especially important that the code we write is readable and searchable. A variable without a name can't help us understand the program, and it also hurts readers. Remember: Make sure it is searchable.

Difference

time.sleep(86400);

What the fuck, God doesn't know what 86400 is

Good

#  Declare variables in the global namespace, 1 How many seconds are there in the day 
SECONDS_IN_A_DAY = 60 * 60 * 24

time.sleep(SECONDS_IN_A_DAY)

It's much clearer.

4. Use self-descriptive variables

Difference

address = 'One Infinite Loop, Cupertino 95014'
city_zip_code_regex = r'^[^,\\]+[,\\\s]+(.+?)\s*(\d{5})?$'
matches = re.match(city_zip_code_regex, address)

save_city_zip_code(matches[1], matches[2])

matches [1] has no role in self-explaining who you are

1-like

address = 'One Infinite Loop, Cupertino 95014'
city_zip_code_regex = r'^[^,\\]+[,\\\s]+(.+?)\s*(\d{5})?$'
matches = re.match(city_zip_code_regex, address)

city, zip_code = matches.groups()
save_city_zip_code(city, zip_code ) 

You should understand that matches. groups () is automatically unpacked into two variables, city, zip_code

Good

address = 'One Infinite Loop, Cupertino 95014'
city_zip_code_regex = r'^[^,\\]+[,\\\s]+(?P<city>.+?)\s*(?P<zip_code>\d{5})?$'
matches = re.match(city_zip_code_regex, address)

save_city_zip_code(matches['city'], matches['zip_code'])

5. Don't force readers to guess the meaning of variables, clear is better than obscure

Difference

current_date: str = datetime.date.today().strftime("%y-%m-%d")

0

What is seq? Sequence? What sequence? No one knows, only by looking down.

Good

current_date: str = datetime.date.today().strftime("%y-%m-%d")

1

Expressed in locations, 1 you can see that this is a tuple composed of several regions

6. Don't add unnecessary context

If your class name already tells you something, don't repeat the description of variable names

Difference

current_date: str = datetime.date.today().strftime("%y-%m-%d")

2

Feel gilding the lily. If it is unnecessary, don't add entities.

Good

class Car:
  make: str
  model: str
  color: str

7. Use default parameters instead of short circuit operation and conditional operation

Difference

current_date: str = datetime.date.today().strftime("%y-%m-%d")

4

Good

current_date: str = datetime.date.today().strftime("%y-%m-%d")

5

This should be understandable, since the function needs to deal with variables without parameters, why not specify it at the time of definition?