Question

我有一个简单的多线程代码，其中一些线程将项放入队列，一些线程从队列中获取项： https://repl.it/@chuoi123/simpleThreading

如果您不想访问上面的链接，请输入完整代码：

import matplotlib.pyplot as plt

fig, ax = plt.subplots()

train_errors = [1,2,3,4,5]
val_errors = [2,1,4,2,3]
test_errors = [5,4,3,2,1]
X = list("ABCDE")

x1 = [i-0.2 for i in range(len(train_errors))]
x2 = [i for i in range(len(train_errors))]
x3 = [i+0.2 for i in range(len(train_errors))]

ax.bar(x1, train_errors, width=0.2, color='b', label="Train Errors")
ax.bar(x2, val_errors, width=0.2, color='g', label="Val Errors")
ax.bar(x3, test_errors, width=0.2, color='r', label="Test Errors")

ax.set_xticks(x2)
ax.set_xticklabels(X)

ax.legend()

ax.set_xlabel('Models')
ax.set_ylabel('RMSE')
ax.set_title('Regression Models Comparison')
plt.show()

我的问题是放线程并且线程不会同时运行，因此一种类型在代码中以其顺序运行。当前代码的结果：

import threading
import queue
import time

def PutWorker(maxValue):
    global item
    while True:
        with putLock:
            if item > maxValue:
                break
            q.put(item)
            print('Added item ' + str(item))
            item += 1
        time.sleep(0.5)

def GetWorker():
    while True:
        item = q.get()
        if item is None:
            break
        with getLock:
            print('Deleted item ' + str(item))
        q.task_done()
        time.sleep(1)

## main process from here
q = queue.Queue()
threads = []
putLock = threading.Lock()
getLock = threading.Lock()
item = 1

while True:
    try:
        numValue = int(input('Number of items in queue: '))
        numThreadsGet = int(input('Number of getting threads: '))
        numThreadsPut = int(input('Number of putting threads: '))
        break
    except:
        print('Input must be ingeter.')

for i in range(numThreadsPut):
    t = threading.Thread(target=PutWorker(numValue),daemon = True)
    t.start()
    threads.append(t)

for i in range(numThreadsGet):
    t = threading.Thread(target=GetWorker,daemon = True)
    t.start()
    threads.append(t)

我想要这样的结果：

Added item 1
Added item 2
Added item 3
Added item 4
Added item 5
...
Deleted item 1
Deleted item 2
Deleted item 3
Deleted item 4
Deleted item 5
...

为什么会发生这种情况以及我可以做些什么来归档我的目标？

编辑：在@ user68014的答案中尝试解决方案之后，我发现另一种方法是从Added item 1 Added item 2 Deleted item 1 Added item 3 Deleted item 2 Added item 4 Deleted item 3 Added item 5 Deleted item 4 Deleted item 5 ...删除参数，并使用全局变量简单地使用def PutWorker()。

Answer 1

问题在于这一行：

t = threading.Thread(target=PutWorker(numValue),daemon = True)

您实际上调用 PutWorker将目标移至Thread。所以在实际创建线程之前都会发生这种情况。你应该传递函数本身。

类似于：

t = threading.Thread(target=PutWorker, ...

没有参数，没有调用，它只是一个函数（Thread会调用它来启动线程）

由于它有一个参数，你需要＆＃34; Curry＆＃34;那个。我这样做：

from functools import partial

...

t = threading.Thread(target=partial(PutWorker, numValue), ...

线程不会同时运行

1 个答案: