如何收集所有列印內容并將它們保存在Python中的txt中？

我想收集所有的列印內容并將它們保存在一個 txt 檔案中。我使用這個答案的方法來生成和收集日志。我也使用 a threading，因為在我的真實環境中，get_logs并且make_logs在不同的執行緒中。

import sys
import io
import time
import threading
import traceback

class MyThread(threading.Thread):
    def __init__(self, func, args):
        super(MyThread, self).__init__()
        self.func = func
        self.args = args

    def run(self):
        try:
            self.result = self.func(*self.args)
        except Exception as e:
            f = traceback.format_exc()
            print(f'{f}')
            
    def get_result(self):
        try:
            return self.result
        except Exception:
            return None

def make_logs(delay):
    for i in range(100):
        print(i)
        print("\n")
        time.sleep(delay)


def get_logs(t1):
    if t1.is_alive():
        sys.stdout = old_stdout
        whatWasPrinted = buffer.getvalue()
        with open("output.txt", "w") as text_file:
            text_file.write(whatWasPrinted)
        time.sleep(1)
        get_logs(t1)
    

def do_it():
    t1 = MyThread(make_logs, args=(1,))
    t2 = MyThread(get_logs, args=(t1,))
    t1.start(), t2.start()
    t1.join(), t2.join()


old_stdout = sys.stdout
sys.stdout = buffer = io.StringIO()
do_it()
    

但是，當我執行此代碼時，我只能將第一個 elment(0) 寫入 txt 檔案。有誰知道為什么？謝謝。

uj5u.com熱心網友回復：

您可以將 sys.stdout 設定為檔案物件以重定向輸出：

import sys
sys.stdout = open(PATH_TO_LOG_FILE, "w")
print('test')
do_it()
sys.stdout.close()

你也可以使用contextlib.redirect_stdout：（適用于 python 3.4 ）

from contextlib import redirect_stdout

with open('help.txt', 'w') as f:
    with redirect_stdout(f):
        print('it now prints to `help.text`')

uj5u.com熱心網友回復：

您不需要兩個執行緒來捕獲前 N 秒 - 您可以撰寫一個類似檔案的物件，io.StringIO當它已經足夠時停止寫入任何支持物件（這里它只是派生但可以包裝另一個 IO）。

import contextlib
import io
import threading
import time


def make_logs(n, delay):
    for i in range(n):
        print(i)
        print("\n")
        time.sleep(delay)


class StdoutCapturer(io.StringIO):
    def __init__(self, time_limit):
        super().__init__()
        self.time_limit = time_limit
        # This could be initialized later, at the first write:
        self.start_time = time.time()

    def write(self, s: str) -> int:
        elapsed = time.time() - self.start_time
        if elapsed < self.time_limit:
            return super().write(s)
        return 0


if __name__ == "__main__":
    sio = StdoutCapturer(time_limit=3.1)
    with contextlib.redirect_stdout(sio):
        t = threading.Thread(target=make_logs, args=(5, 1))
        t.start()
        t.join()
    print(repr(sio.getvalue()))

這列印出來

'0\n\n\n1\n\n\n2\n\n\n3\n\n\n'

編輯

根據評論，我認為包裝另一個 IO 的含義并不清楚，所以這是一個將前 N 秒寫入檔案的變體......

class TimeLimitedFileWrapper(io.TextIOWrapper):

    def __init__(self, raw_file, *, time_limit):
        super().__init__(raw_file, encoding="utf-8")
        self.start_time = time.time()
        self.time_limit = time_limit

    def write(self, s: str) -> int:
        elapsed = time.time() - self.start_time
        if elapsed < self.time_limit:
            return super().write(s)
        return 0


if __name__ == '__main__':
    with open("foo.txt", "wb") as f:
        with contextlib.redirect_stdout(TimeLimitedFileWrapper(raw_file=f, time_limit=3.1)):
            t = threading.Thread(target=make_logs, args=(5, 1))
            t.start()
            t.join()

    with open("foo.txt", "rb") as f:
        print(repr(f.read()))

輸出是一樣的。

標籤：

上一篇：Cordova沒有看到已安裝的AndroidSDK

下一篇：在這種情況下，如何用信號量或互斥鎖替換佇列