Python 通过截断从文件中删除最终字符_Python

Python 通过截断从文件中删除最终字符

python

Python 通过截断从文件中删除最终字符,python,Python,我想删除python文本文件中的最后一个逗号。该文件如下所示： {"time":"2019-02-12T14:41:25.2424552+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_

我想删除python文本文件中的最后一个逗号。该文件如下所示：

{"time":"2019-02-12T14:41:25.2424552+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"GetAlteracion","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531"},"response":null,"status":200},  
{"time":"2019-02-12T14:41:25.5525828+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Expedientes_dmz_","service":"GetObligatoriedadDocumental","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531","tipo_alteracion":"ALT_1","id_expediente":""},"response":null,"status":400},  
{"time":"2019-02-12T14:41:25.9169746+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"Ubicar","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531","epsg":"EPSG:4326"},"response":null,"status":200},
{"time":"2019-02-12T14:41:29.8222248+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"GetAlteracion","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819"},"response":null,"status":200},  
{"time":"2019-02-12T14:41:29.9708861+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Expedientes_dmz_","service":"GetObligatoriedadDocumental","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","tipo_alteracion":"ALT_1","id_expediente":""},"response":null,"status":400} ,  
{"time":"2019-02-12T14:41:30.3077709+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"Ubicar","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","epsg":"EPSG:4326"},"response":null,"status":200},  
{"time":"2019-02-12T14:41:38.7145697+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Documentos_dmz_","service":"obtenerDocumento","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","documento":"E000226847","control":11},"response":null,"status":200},

我想去掉最后一行的逗号。在查看了大量示例后，我尝试了以下代码（以及许多类似的选项）：

但这不起作用。有什么帮助吗

编辑

逗号和

'}

之间没有空格。如果文件以逗号结尾，我们办公室里的程序（我没有访问权限）会给出一个错误。我需要的是只删除文件最后一行中的最后一个逗号，而不是删除每一行中的最后一个逗号，然后以以下方式返回文件：

{"time":"2019-02-12T14:41:25.2424552+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"GetAlteracion","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531"},"response":null,"status":200},  
{"time":"2019-02-12T14:41:25.5525828+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Expedientes_dmz_","service":"GetObligatoriedadDocumental","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531","tipo_alteracion":"ALT_1","id_expediente":""},"response":null,"status":400},  
{"time":"2019-02-12T14:41:25.9169746+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"Ubicar","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531","epsg":"EPSG:4326"},"response":null,"status":200},
{"time":"2019-02-12T14:41:29.8222248+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"GetAlteracion","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819"},"response":null,"status":200},  
{"time":"2019-02-12T14:41:29.9708861+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Expedientes_dmz_","service":"GetObligatoriedadDocumental","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","tipo_alteracion":"ALT_1","id_expediente":""},"response":null,"status":400},  
{"time":"2019-02-12T14:41:30.3077709+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"Ubicar","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","epsg":"EPSG:4326"},"response":null,"status":200},  
{"time":"2019-02-12T14:41:38.7145697+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Documentos_dmz_","service":"obtenerDocumento","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","documento":"E000226847","control":11},"response":null,"status":200}

编辑2 最后，解决方案对我有效！：

with open('data.txt', 'ab'):
    f.seek(-1, 2)
    f.truncate()

使用以下命令：

res = your_string.rstrip(',')

为了

希望能有帮助

谢谢

我注意到

，

不是数据中的最后一个符号，这就是为什么您的解决方案以及

rstrip（'，'）

无法工作的原因。使用

替换：
with open('data.txt', 'r') as f:
    data = f.read().replace('} ,', '}')

with open('data.txt', 'w') as f:
    f.write(data)

此脚本删除每行上的最后一个逗号（因为'}，
仅出现在每行的末尾），输出时您将看到以下内容：
{"time":"2019-02-12T14:41:25.2424552+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"GetAlteracion","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531"},"response":null,"status":200}
{"time":"2019-02-12T14:41:25.5525828+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Expedientes_dmz_","service":"GetObligatoriedadDocumental","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531","tipo_alteracion":"ALT_1","id_expediente":""},"response":null,"status":400}
{"time":"2019-02-12T14:41:25.9169746+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"Ubicar","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_85531","epsg":"EPSG:4326"},"response":null,"status":200}
{"time":"2019-02-12T14:41:29.8222248+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"GetAlteracion","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819"},"response":null,"status":200}
{"time":"2019-02-12T14:41:29.9708861+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Expedientes_dmz_","service":"GetObligatoriedadDocumental","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","tipo_alteracion":"ALT_1","id_expediente":""},"response":null,"status":400}
{"time":"2019-02-12T14:41:30.3077709+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Alteraciones_Primitivas_dmz_","service":"Ubicar","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","epsg":"EPSG:4326"},"response":null,"status":200}
{"time":"2019-02-12T14:41:38.7145697+01:00","ip":"::1","browser":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.96 Safari/537.36","user":"28969523B","profile":"SUMUM_D?99?2017?2","controller":"Documentos_dmz_","service":"obtenerDocumento","delegacion":null,"municipio":null,"method":"GET","parameters":{"id_alteracion":"11_31_17819","documento":"E000226847","control":11},"response":null,"status":200}

这个怎么样
rf = open('data.txt').read()
with open('data.txt', 'w') as wf:
    wf.write(rf[:-3])

您的代码无法工作，因为在写模式下打开文件会立即将其截断为零长度。您需要附加模式，该模式将使用任何现有文件的内容
忽略一个字节等于一个字符的假设（Unicode进入图片后，情况并非总是如此），并假设文件末尾没有换行符，并且您希望保留空格，这样应该可以：
with open('data.txt', 'ab'):
    f.seek(-1, 2)
    f.truncate()

此解决方案定位最后一个索引的索引
}
在最后一行中，并将字符串替换为索引
以后可以选择重命名“新”文件
with open("datain.txt", 'r') as f_in, open('dataout.txt', 'w') as f_out:
    last = None
    for l in f_in.readlines():
        if last:
            f_out.write(last)
        last = l
    i = last.rfind("}")
    f_out.write(last[:i+1])

您也可以这样做，但是我不知道它如何处理编码，循环可能会受到更多限制，这样您就不会截断整个文件
import os
with open("datain.txt", "r+") as f:
    f.seek(0, os.SEEK_END)
    pos = f.tell()

    while pos > 0:
        f.seek(pos)
        c = f.read(1).encode('utf-8')
        if c == b'}':
            break
        pos = f.tell() - 2
    f.truncate(pos)

可能的重复您是否确定逗号是文件中的最后一个字符，并且没有任何隐藏的内容（例如空格、回车符或换行符（\r或\n））？@liamhawkins您提到的潜在重复假定一个字符=一个字节。这将替换所有逗号？他们特别想删除fileNope中的最后一个逗号。最后一个原因是数据格式（这里唯一的额外空间：}，
）对于一个可能解释得更清楚的问题来说是一个有点脆弱的解决方案。每一行都有额外的空间。按住Ctrl+F键，输入字符串}，，您将在每个字符串上看到它。我在这里遗漏了什么？@liamhawkins我已经更新了我的答案，让事情变得更清楚。这是一个很好的解决方案，但只有当逗号是最后一个字符时才有效，我怀疑这里的情况是否如此。问题显然是试图使用文件截断，大概是为了“效率”。此方法创建新文件，而不是缩短现有文件。
import os
with open("datain.txt", "r+") as f:
    f.seek(0, os.SEEK_END)
    pos = f.tell()

    while pos > 0:
        f.seek(pos)
        c = f.read(1).encode('utf-8')
        if c == b'}':
            break
        pos = f.tell() - 2
    f.truncate(pos)