在Python中，如何在X个时间之后替换文件中的字符串？

前提解释：

# Main.py

while True:
    f=open("data.txt","a+")
    a = str(scan())+"\n"
    f.write(a);
    log.log("Wrote to file")
    log.log(a)
    with open("data.txt","rt") as fin:
        with open("data.txt","wt")as fout:
            for line in fin:
                fout.write(line.replace("scan()", "scan()"))
    f.close()

[26.07, 32.31, 93.73, False] #it constantly overwrites this line.

    #print out 10 strings of text
    [23.07, 32.31, 93.73, False] 
    [27.03, 36.34, 93.73, False] 
    [26.07, 34.36, 93.73, False] 
    [28.02, 32.21, 93.73, False] 
    [24.03, 22.31, 93.73, False] 
    [22.07, 28.31, 93.73, False] 
    [29.04, 32.21, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False]

#new string of text comes in [26.07, 32.31, 93.73, True]
expected output:
   [27.03, 36.34, 93.73, False] 
   [26.07, 34.36, 93.73, False] 
   [28.02, 32.21, 93.73, False] 
   [24.03, 22.31, 93.73, False] 
   [22.07, 28.31, 93.73, False] 
   [29.04, 32.21, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, True]  # replaces the string one, adding this new data into the list.

我有一个Python脚本Main.py，它收集距离和温度，并将它们发送到一个文本文件Data.txt。目前我有它，所以每次它都会替换文本字符串

编辑：

# Main.py

while True:
    f=open("data.txt","a+")
    a = str(scan())+"\n"
    f.write(a);
    log.log("Wrote to file")
    log.log(a)
    with open("data.txt","rt") as fin:
        with open("data.txt","wt")as fout:
            for line in fin:
                fout.write(line.replace("scan()", "scan()"))
    f.close()

[26.07, 32.31, 93.73, False] #it constantly overwrites this line.

    #print out 10 strings of text
    [23.07, 32.31, 93.73, False] 
    [27.03, 36.34, 93.73, False] 
    [26.07, 34.36, 93.73, False] 
    [28.02, 32.21, 93.73, False] 
    [24.03, 22.31, 93.73, False] 
    [22.07, 28.31, 93.73, False] 
    [29.04, 32.21, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False]

#new string of text comes in [26.07, 32.31, 93.73, True]
expected output:
   [27.03, 36.34, 93.73, False] 
   [26.07, 34.36, 93.73, False] 
   [28.02, 32.21, 93.73, False] 
   [24.03, 22.31, 93.73, False] 
   [22.07, 28.31, 93.73, False] 
   [29.04, 32.21, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, True]  # replaces the string one, adding this new data into the list.

目前它只打印一个文本字符串，代码会重复地覆盖这一行，我想要的是代码在覆盖最早的一行之前打印该字符串的10行，就像下面的示例一样

示例：

# Main.py

while True:
    f=open("data.txt","a+")
    a = str(scan())+"\n"
    f.write(a);
    log.log("Wrote to file")
    log.log(a)
    with open("data.txt","rt") as fin:
        with open("data.txt","wt")as fout:
            for line in fin:
                fout.write(line.replace("scan()", "scan()"))
    f.close()

[26.07, 32.31, 93.73, False] #it constantly overwrites this line.

    #print out 10 strings of text
    [23.07, 32.31, 93.73, False] 
    [27.03, 36.34, 93.73, False] 
    [26.07, 34.36, 93.73, False] 
    [28.02, 32.21, 93.73, False] 
    [24.03, 22.31, 93.73, False] 
    [22.07, 28.31, 93.73, False] 
    [29.04, 32.21, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False]

#new string of text comes in [26.07, 32.31, 93.73, True]
expected output:
   [27.03, 36.34, 93.73, False] 
   [26.07, 34.36, 93.73, False] 
   [28.02, 32.21, 93.73, False] 
   [24.03, 22.31, 93.73, False] 
   [22.07, 28.31, 93.73, False] 
   [29.04, 32.21, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, True]  # replaces the string one, adding this new data into the list.

实际输出：

# Main.py

while True:
    f=open("data.txt","a+")
    a = str(scan())+"\n"
    f.write(a);
    log.log("Wrote to file")
    log.log(a)
    with open("data.txt","rt") as fin:
        with open("data.txt","wt")as fout:
            for line in fin:
                fout.write(line.replace("scan()", "scan()"))
    f.close()

[26.07, 32.31, 93.73, False] #it constantly overwrites this line.

    #print out 10 strings of text
    [23.07, 32.31, 93.73, False] 
    [27.03, 36.34, 93.73, False] 
    [26.07, 34.36, 93.73, False] 
    [28.02, 32.21, 93.73, False] 
    [24.03, 22.31, 93.73, False] 
    [22.07, 28.31, 93.73, False] 
    [29.04, 32.21, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False]

#new string of text comes in [26.07, 32.31, 93.73, True]
expected output:
   [27.03, 36.34, 93.73, False] 
   [26.07, 34.36, 93.73, False] 
   [28.02, 32.21, 93.73, False] 
   [24.03, 22.31, 93.73, False] 
   [22.07, 28.31, 93.73, False] 
   [29.04, 32.21, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, True]  # replaces the string one, adding this new data into the list.

问题：

# Main.py

while True:
    f=open("data.txt","a+")
    a = str(scan())+"\n"
    f.write(a);
    log.log("Wrote to file")
    log.log(a)
    with open("data.txt","rt") as fin:
        with open("data.txt","wt")as fout:
            for line in fin:
                fout.write(line.replace("scan()", "scan()"))
    f.close()

[26.07, 32.31, 93.73, False] #it constantly overwrites this line.

    #print out 10 strings of text
    [23.07, 32.31, 93.73, False] 
    [27.03, 36.34, 93.73, False] 
    [26.07, 34.36, 93.73, False] 
    [28.02, 32.21, 93.73, False] 
    [24.03, 22.31, 93.73, False] 
    [22.07, 28.31, 93.73, False] 
    [29.04, 32.21, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False]

#new string of text comes in [26.07, 32.31, 93.73, True]
expected output:
   [27.03, 36.34, 93.73, False] 
   [26.07, 34.36, 93.73, False] 
   [28.02, 32.21, 93.73, False] 
   [24.03, 22.31, 93.73, False] 
   [22.07, 28.31, 93.73, False] 
   [29.04, 32.21, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, True]  # replaces the string one, adding this new data into the list.

如何使其在替换字符串之前打印出至少10行文本

需要的输出示例：

# Main.py

while True:
    f=open("data.txt","a+")
    a = str(scan())+"\n"
    f.write(a);
    log.log("Wrote to file")
    log.log(a)
    with open("data.txt","rt") as fin:
        with open("data.txt","wt")as fout:
            for line in fin:
                fout.write(line.replace("scan()", "scan()"))
    f.close()

[26.07, 32.31, 93.73, False] #it constantly overwrites this line.

    #print out 10 strings of text
    [23.07, 32.31, 93.73, False] 
    [27.03, 36.34, 93.73, False] 
    [26.07, 34.36, 93.73, False] 
    [28.02, 32.21, 93.73, False] 
    [24.03, 22.31, 93.73, False] 
    [22.07, 28.31, 93.73, False] 
    [29.04, 32.21, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False] 
    [26.07, 32.31, 93.73, False]

#new string of text comes in [26.07, 32.31, 93.73, True]
expected output:
   [27.03, 36.34, 93.73, False] 
   [26.07, 34.36, 93.73, False] 
   [28.02, 32.21, 93.73, False] 
   [24.03, 22.31, 93.73, False] 
   [22.07, 28.31, 93.73, False] 
   [29.04, 32.21, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, False] 
   [26.07, 32.31, 93.73, True]  # replaces the string one, adding this new data into the list.

---

你可以考虑使用<代码> Time.Scess（）/Script >，以便每秒只写一次文件。

import time
import numpy as np

def scan():
    # your scanner here. 
    return list(np.random.randint(1, 10, 4))

a_list = list()

while True:
    a = str(scan()) + "\n"
    a_list.insert(0, a)
    a_list = a_list[:10]

    with open("data.txt", "wt") as fout:
        fout.write(''.join(a_list))
        time.sleep(1)

试试这个：

while True:
    txt = open("data.txt", "r").read()
    txt = txt.split("\n")
    if len(txt) == 10:
        txt.pop(0)
        txt.append("what you want to write")
    else:
        txt.append("what you want to write")
    f = open("data.txt", "w")
    f.write("\n".join(txt))

---

谢谢你的建议，它确实像预期的那样附加了，但由于某些原因，即使在删除时间之后，它仍然非常慢。sleep@yongjie可能是因为你的扫描功能，扫描功能仍然每1秒打印一次，所以我认为这不是问题所在，我想这可能是因为我使用的是覆盆子Pi，它可能没有足够的处理能力？谢谢你的建议，我已经尝试了你的解决方案，但不幸的是，我无法让它打印scan（）字符串。我尝试了

txt.append（str=（scan（））

但是没有用，你有解决办法吗？你可以将扫描返回值存储在一个变量中，然后在txtAh中附加一个字符串谢谢，我现在让它运行了，但我相信这不是我要找的函数，我要找的文本长度代码检查就是保持一个常量行，就像我的示例中一样。Regardless，再次感谢你的时间，它仍然帮助我进一步理解python。欢迎你，如果你编辑你的答案澄清问题，我将很乐意帮助你