如何使python代码更高效/更整洁

Question

Hey there guys/girls I was looking towards improving the code I have written as I want to make it easier to read and more comprehensive. It is mainly the addtolist function that is taking up a lot of space but the problem is that I only know how to complete that task using that way, if somebody would be kind enough to teach me how to make it tidier.

#speedingticket.py
#Trying to make a efficient and small script that can be used to track 
# illegial drivers.
#Jason Singh, 21 February

#Modules
import time

#Variables
fine = 0
wanted_first = ["James", "Helga", "Zachary"]
wanted_last = ["Wilson" , "Norman", "Conroy "]

#Lists
a = [1, 2, 3, 4, 5, 6, 7, 8, 9]
b = [10, 11, 12, 13, 14]
c = [15, 16, 17, 18, 19]
d = [20, 21, 22, 23, 24]
e = [25, 26, 27, 28, 29]
f = [30, 31, 32, 33, 34]
g = [35, 36, 37, 38, 39]
h = [40, 41, 42, 43, 44]
i = [45]
finelist = []

#Functions
def addtolist(CarSpeed, SpeedLimit, fine):
    CarOverLimit = CarSpeed - SpeedLimit
    if CarOverLimit in a:
        fine = 30
        finelist.append(fine)
        print("$30 FINE")
    elif CarOverLimit in b:
        fine = 80
        finelist.append(fine)
        print("$80 FINE")
    elif CarOverLimit in c:
        fine = 120
        finelist.append(fine)
        print("$120 FINE")
    elif CarOverLimit in d:
        fine = 170
        finelist.append(fine)
        print("$170 FINE")
    elif CarOverLimit in e:
        fine = 230
        finelist.append(fine)
        print("$230 FINE")
    elif CarOverLimit in f:
        fine = 300
        finelist.append(fine)
        print("$300 FINE")
    elif CarOverLimit in g:
        fine = 400
        finelist.append(fine)
        print("$400 FINE")
    elif CarOverLimit in h:
        fine = 510
        finelist.append(fine)
        print("$510 FINE")
    elif CarOverLimit >= 45:
        fine = 630
        finelist.append(fine)
        print("$630 FINE")
    else:
        print("NO FINE")

def wanted(First_Name, Last_Name):
    if First_Name in wanted_first and Last_Name in wanted_last:
        print("========================================")
        print("WARNING! WARNING! WARNING!")
        print("{} {} HAS A ARREST WARRANT".format(First_Name, Last_Name))
        print("========================================")
    else:
        print("{} {} IS CLEAR\n".format(First_Name, Last_Name))

def menu():
    print("______________________\n")
    print("SPEED FINE CALCULATOR")
    print("______________________\n")
    print("1 | CALCULATE FINES")
    print("2 | TOTAL FINES")
    print("3 | EXIT\n")
    x = input("ENTER 1 | 2 | 3\n")
    return x

#Main routine that runs in loop
while True:
    task = menu()
    if task == "1":
            First_Name = input("DRIVER'S FIRST NAME: \n").upper()
            Last_Name =  input("DRIVER'S LAST NAME: \n").upper()
            SpeedLimit = int(input("ROAD SPEED LIMIT: \n"))
            CarSpeed = int(input("DRIVER'S SPEED: \n"))
            addtolist(CarSpeed, SpeedLimit, fine)
            wanted(First_Name, Last_Name)
    elif task == "2":
            if sum(finelist) == 0:
                print("NO RECORDS")
            else:
                print("TOTAL FINE: {}".format(sum(finelist)))
                time.sleep(1)
                print("TOTAL AMOUNT OF FINES: {}".format(len(finelist)))
    elif task == "3":
        exit()
    else:
        print("INPUT VALUE NOT ALLOWED")

Answer 1

I would restructure the table and separate the fine computation from both output and list management.
Something like this:

def compute_fine(speed, speed_limit):
    fine_limits = [(45, 630),(40, 510),(35, 400),(30, 300),(25, 230),(20, 170),(15, 120),(10, 80),(0, 30)]
    over = speed - speed_limit
    for limit, fine in fine_limits:
        if over > limit:
            return fine
    return 0


fines = []
while True:
    task = menu()
    if task == "1":
            First_Name = input("DRIVER'S FIRST NAME: \n").upper()
            Last_Name =  input("DRIVER'S LAST NAME: \n").upper()
            SpeedLimit = int(input("ROAD SPEED LIMIT: \n"))
            CarSpeed = int(input("DRIVER'S SPEED: \n"))
            fine = compute_fine(CarSpeed, SpeedLimit)
            if fine > 0:
                fines.append(fine)
                print("${} FINE".format(fine))
            else:
                print("NO FINE")
            wanted(First_Name, Last_Name)
    elif task == "2":
            if len(fines) == 0:
                print("NO RECORDS")
            else:
                print("TOTAL FINE: {}".format(sum(fines)))
                time.sleep(1)
                print("TOTAL AMOUNT OF FINES: {}".format(len(fines)))
    elif task == "3":
        exit()
    else:
        print("INPUT VALUE NOT ALLOWED")

Answer 2

You can get rid of all your lists and just use greater than, less than and equal to type of functions in your if statements. Since there doesn't seem to be a pattern to how the fine increases, I'm not sure what else you could do.

And things that aren't affected directly by the If, can go outside of the if statements. And you can substitute out our print statements. And if you absolutely need it to say "NO FINE" instead of "$0 FINE" then you can double your if statement

def addtolist(CarSpeed, SpeedLimit, fine):
    CarOverLimit = CarSpeed - SpeedLimit
    if (CarOverLimit <= 0):
        print("NO FINE")
    else:
        if (CarOverLimit > 0) & (CarOverLimit < 10):
            fine = 30
        elif (CarOverLimit >= 10) & (CarOverLimit < 15):
            fine = 80
        elif (CarOverLimit >= 15) & (CarOverLimit < 20):
            fine = 120
        elif (CarOverLimit >= 20) & (CarOverLimit < 25):
            fine = 170
        elif (CarOverLimit >=25) & (CarOverLimit < 30):
            fine = 230
        elif (CarOverLimit >= 30) & (CarOverLimit < 35):
            fine = 300
        elif (CarOverLimit >= 35) & (CarOverLimit < 40):
            fine = 400
        elif (CarOverLimit >= 40) & (CarOverLimit < 45):
            fine = 510
        elif CarOverLimit >= 45:
            fine = 630
        finelist.append(fine)
        print(f"${fine} FINE")

You also don't need to print out each line, you can just put triple quotes around something to get a string over multiple lines. And you can use "\\n" to create a new line. And as long as you have 3.6 or higher python, you can use fstring instead of format. For example, I did it just on your wanted function

def wanted(First_Name, Last_Name):
    if First_Name in wanted_first and Last_Name in wanted_last:
        print(f"""========================================
        \nWARNING! WARNING! WARNING!\n{First_Name} {Last_Name} HAS A ARREST WARRANT"
         ========================================""")
    else:
        print(f"{First_Name} {Last_Name} IS CLEAR\n")

Hope that helps a little.

Answer 3

Here is an elegant dictionnary approach you could use, and after I also wrote another solution that uses many ifs like your.

finelist = []
fine = 0
# Define in a single variable all the overspeed/fine combinations.
fines_for_each_overspeed = {"0":  0,
                            "9": 30,
                            "14": 80,
                            "19": 120,
                            "20": 170,
                            "24": 230,
                            "29": 300,
                            "34": 400,
                            "39": 510,
                            "44": 630}

def addtolist(CarSpeed, SpeedLimit):
    CarOverLimit = CarSpeed - SpeedLimit

    # Go through the dictionnary possible overspeeds until you find one that matches the car's. 
    for overspeed in fines_for_each_overspeed.keys():
        if CarOverLimit <= int(overspeed):
            break
    # Then your fine is just the value associated to the overspeed key.
    fine = fines_for_each_overspeed[overspeed]

    if fine > 0:
        print("${} FINE".format(fine))
        finelist.append(fine)
    else:
        print("NO FINE")

Now for your way. Your lists are not needed elsewhere so you can write them directly in the condition like if CarOverLimit in [1, 2, 3, 4, 5, 6, 7, 8, 9] . In this particular case you are just checking numerical values so use <= directly for more clarity.

You can also move the finelist.append() and print at the end instead of using them on every line.

finelist = []
fine = 0

#Functions
def addtolist(CarSpeed, SpeedLimit, fine):
    CarOverLimit = CarSpeed - SpeedLimit
    if 1 <= CarOverLimit <= 9:
        fine = 30
    elif 10 <= CarOverLimit <= 14:
        fine = 80
    elif 15 <= CarOverLimit <= 19:
        fine = 120
    elif 20 <= CarOverLimit <= 24:
        fine = 170
    elif 25 <= CarOverLimit <= 29:
        fine = 230
    elif 30 <= CarOverLimit <= 34:
        fine = 300
    elif 35 <= CarOverLimit <= 39:
        fine = 400
    elif 40 <= CarOverLimit <= 44:
        fine = 510
    elif 45 <= CarOverLimit:
        fine = 630

    if fine > 0:
        print("${} FINE".format(fine))
        finelist.append(fine)
    else:
        print("NO FINE")