英文:
Python Thread : TypeError: __main__.generate_num() argument after * must be an iterable, not Event
问题
from threading import Thread, Event
import queue
import random
def generate_num(e):
print('e', e.is_set())
while True:
if e.is_set():
print('g', random.randint(15, 20))
else:
print('g', 0)
def start_generating():
i = 0
e = Event()
r_thread = Thread(target=generate_num, args=(e,), daemon=True).start() # Fix the args tuple
print('starting')
while True:
print('i', i)
if i % 5 == 0:
e.set()
if i == 12:
exit(0)
i += 1
start_generating()
错误信息表明在调用generate_num函数时，参数应该是可迭代的，但传递了一个Event对象。为了修复这个问题，你需要将参数传递给generate_num函数时放入一个元组中，就像上面的代码示例中修复的那样。
英文:
I am experiment the Threads with Event
from threading import Thread, Event
import queue
import random
def generate_num(e):
print('e',e.is_set())
while True:
if e.is_set():
print('g', random.randint(15, 20))
else:
print('g', 0)
def start_generating():
i = 0
e = Event()
r_thread = Thread(target=generate_num, args=(e), daemon=True).start()
print('starting')
while True:
print('i', i)
if i %5 == 0:
e.set()
if i ==12:
exit(0)
i+=1
start_generating()
My aim is that when i becomes 5 or 10, it should print the random number, otherwise it should print 0.
But, I got this error
starting
i 0
i 1
i 2
Exception in thread Thread-6 (generate_num):
Traceback (most recent call last):
i 3
i 4
i 5
i 6
i 7
i 8
i 9
File "/usr/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
i 10
iself.run()
File "/usr/lib/python3.10/threading.py", line 953, in run
11
self._target(*self._args, **self._kwargs)
TypeError: __main__.generate_num() argument after * must be an iterable, not Event
i 12
How to solve this, thanks
答案1
得分: 0
如评论中指出并且在错误中也提到，args 不是一个可迭代对象，更具体地说，它应该是一个元组，这通常是 args 参数应该的形式。
创建只包含一个元素的元组需要在元素后面加上逗号 ,。
one_element_tuple = (1,)
所以只需这样做：
from threading import Thread, Event
import queue
import random
def generate_num(e):
print('e', e.is_set())
while True:
if e.is_set():
print('g', random.randint(15, 20))
else:
print('g', 0)
def start_generating():
i = 0
e = Event()
r_thread = Thread(target=generate_num, args=(e,), daemon=True).start()
print('starting')
while True:
print('i', i)
if i % 5 == 0:
e.set()
if i == 12:
exit(0)
i += 1
start_generating()
英文:
As pointed out in the comments and also in the error the args are not an iterable or to be more specific a tuple, which is what the args argument normally should be.
Creating a tuple with only one element needs a trailing ,
one_element_tuple = (1,)
So just do
from threading import Thread, Event
import queue
import random
def generate_num(e):
print('e',e.is_set())
while True:
if e.is_set():
print('g', random.randint(15, 20))
else:
print('g', 0)
def start_generating():
i = 0
e = Event()
r_thread = Thread(target=generate_num, args=(e,), daemon=True).start()
print('starting')
while True:
print('i', i)
if i %5 == 0:
e.set()
if i ==12:
exit(0)
i+=1
start_generating()
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