python - 根据属性计算类的实例

Question

计算特定属性值的实例数

我创建了一个类，名为:bird .该类的每个实例都有两个属性:

• creed (值可以是 "C" 或 "D")，以及
• life (从值 100 开始，并随着程序的执行而变化)。

程序模拟两只活鸟的随机相遇，鸟的变化值life每次相遇后。一旦达到 0，这只鸟就被排除在进一步的互动之外(即死亡)。

经过多次迭代，我想知道每个教派有多少只鸟“活着”。

import random


class Bird:
    Doves = 100
    Crows = 100

    # Initializer / Instance Attributes
    def __init__(self, creed, life):
        self.creed = creed
        self.life = life


def slct_parties():
    first = random.randint(0, (Bird.Crows + Bird.Doves -1))
    second = random.randint(0, (Bird.Crows + Bird.Doves -1))
    while first == second or population[first].life < 1 or population[second].life < 1:
        first = random.randint(0, (Bird.Crows + Bird.Doves - 1))
        second = random.randint(0, (Bird.Crows + Bird.Doves - 1))
    return first, second


#   initiating Population
population = []

for bird in range(0, Bird.Crows):
    population.append(Bird('C', 100))

for bird in range(0, Bird.Doves):
    population.append(Bird('D', 100))

for x in range(1, 1000):
    Contest = slct_parties()
    l1 = population[Contest[0]].life
    l2 = population[Contest[1]].life
    # battle
    if population[Contest[0]].creed != population[Contest[0]].creed:
        if population[Contest[0]].creed == 'D':
            population[Contest[0]].life += 1
            population[Contest[1]].life += 1
        else:
            population[Contest[0]].life += -5
            population[Contest[1]].life += -10
    elif population[Contest[0]].creed == 'C':
        population[Contest[0]].life += 5
        population[Contest[1]].life += -20
    else:
        population[Contest[0]].life += -20
        population[Contest[1]].life += 5

    print("The battle was between {} number {} with {} life, and {} number {} with {} life"
        .format(population[Contest[0]].creed, Contest[0], population[Contest[0]].life, population[Contest[1]].creed,
        Contest[1], population[Contest[1]].life))

经过 1,000 次战斗，一些鸟类已经死亡。几只鸟？哪个信条？

简答

• 单行(感谢 Carcigenicate ) dead_crows = len([bird for bird in population if bird.creed == "c" and bird.life <= 0])

• 函数(感谢 zixuan)

def DeadConter(crd):
    dead = 0
    for bird in population:
        if bird.life <= 0 and bird.creed == crd:
            dead += 1
        else:
            pass
    return dead

Answer 1

您还可以在计算有多少只鸟死亡的类定义之前定义两个从 0 开始的值，例如在一只鸟“死”时添加一个 cDead += 1。 1000 次战斗后，从第一个值中减去 100，从第二个值中减去 100。然后你就会知道每个信条中有多少只鸟还活着。您还可以像这样计算每个信条有多少只鸟死了。

import random

c_dead = 0
d_dead = 0

class Bird:
    Doves = 100
    Crows = 100

    # Initializer / Instance Attributes
    def __init__(self, creed, life):
        self.creed = creed
        self.life = life


def slct_parties():
    first = random.randint(0, (Bird.Crows + Bird.Doves -1))
    second = random.randint(0, (Bird.Crows + Bird.Doves -1))
    while first == second or population[first].life < 1 or population[second].life < 1:
        first = random.randint(0, (Bird.Crows + Bird.Doves - 1))
        second = random.randint(0, (Bird.Crows + Bird.Doves - 1))
    return first, second


#   initiating Population
population = []

for bird in range(0, Bird.Crows):
    population.append(Bird('C', 100))

for bird in range(0, Bird.Doves):
    population.append(Bird('D', 100))

for x in range(1, 1000):
    Contest = slct_parties()
    l1 = population[Contest[0]].life
    l2 = population[Contest[1]].life
    # battle
    if population[Contest[0]].creed != population[Contest[0]].creed:
        if population[Contest[0]].creed == 'D':
            population[Contest[0]].life += 1
            population[Contest[1]].life += 1
        else:
            population[Contest[0]].life += -5
            population[Contest[1]].life += -10
    elif population[Contest[0]].creed == 'C':
        population[Contest[0]].life += 5
        population[Contest[1]].life += -20
    else:
        population[Contest[0]].life += -20
        population[Contest[1]].life += 5

for bird in population:
    if bird.life <= 0:
        if bird.creed == "C":
            c_dead += 1
        elif bird.creed == "D":
            d_dead += 1
        else:
            print("Dead birds failed to count") # should never happen, this is a good check for bugs

print("The battle was between {} number {} with {} life, and {} number {} with {} life"
        .format(population[Contest[0]].creed, Contest[0], population[Contest[0]].life, population[Contest[1]].creed,
        Contest[1], population[Contest[1]].life))
#print dead birds here
print("Number of alive birds")
print(str(100-c_dead) + ": Doves" + " " + str(100-d_dead) + ": Crows")

我添加了 else 行，因为这段代码未经测试，我不知道是否有任何错误。

编辑:代码现在已经过测试，我更改了几行以使其正常工作。