仅从输入变量中提取json数据

Question

我有以下格式的输入数据(Stdout)。有没有办法使用python只提取json格式？

删除行的逻辑，直到我们得到"{“直到结尾"}”，或者从输入变量中提取json格式

输入数据为

    stdout="""nameserver  8.8.8.8
    Hit:1 http://archive.ubuntu.com/ubuntu xenial InRelease
    Hit:2 http://archive.ubuntu.com/ubuntu xenial-updates InRelease
    Hit:3 http://security.ubuntu.com/ubuntu xenial-security InRelease
    Hit:4 http://archive.ubuntu.com/ubuntu xenial-backports InRelease
    Reading package lists...
    Reading package lists...
    Building dependency tree...
    Reading state information...
    fio is already the newest version (2.2.10-1ubuntu1).
    0 upgraded, 0 newly installed, 0 to remove and 50 not upgraded.
    {
      "fio version" : "fio-2.2.10",
      "timestamp" : 1589874145,
      "time" : "Tue May 19 07:42:25 2020",
      "jobs" : [
        {
          "jobname" : "yardstick-fio",
         "groupid" : 0,
          "error" : 0,
          "eta" : 0,
          "elapsed" : 31,
          "read" : {
            "io_bytes" : 11723776,
            "bw" : 585954,
            "short_ios" : 0,
            "drop_ios" : 0,
            "slat" : {
              "min" : 26,
              "max" : 54318,
              "mean" : 38.89,
              "stddev" : 437.20
            },
                 "latency_ms" : {
            "2" : 0.39,
            "4" : 0.07,
            "250" : 0.01,
            "500" : 0.00,
            "750" : 0.00,
            "1000" : 0.00,
            "2000" : 0.00,
            ">=2000" : 0.00
          },

       }
      ],
      "disk_util" : [
        {
          "name" : "vda",
          "read_ios" : 30743,
          "write_ios" : 26938,
          "read_merges" : 0,
          "write_merges" : 11,
          "read_ticks" : 28652,
          "write_ticks" : 29192,
          "in_queue" : 57836,
          "util" : 96.17
        }
      ]
    }"""

新变量(New_stdout)中的预期输出：

{
    "fio version" : "fio-2.2.10",
    "timestamp" : 1589874145,
    "time" : "Tue May 19 07:42:25 2020",
    "jobs" : [
      {
        "jobname" : "yardstick-fio",
       "groupid" : 0,
        "error" : 0,
        "eta" : 0,
        "elapsed" : 31,
        "read" : {
          "io_bytes" : 11723776,
          "bw" : 585954,
          "short_ios" : 0,
          "drop_ios" : 0,
          "slat" : {
            "min" : 26,
            "max" : 54318,
            "mean" : 38.89,
            "stddev" : 437.20
          },
               "latency_ms" : {
          "2" : 0.39,
          "4" : 0.07,
          "250" : 0.01,
          "500" : 0.00,
          "750" : 0.00,
          "1000" : 0.00,
          "2000" : 0.00,
          ">=2000" : 0.00
        },

     }
    ],
    "disk_util" : [
      {
        "name" : "vda",
        "read_ios" : 30743,
        "write_ios" : 26938,
        "read_merges" : 0,
        "write_merges" : 11,
        "read_ticks" : 28652,
        "write_ticks" : 29192,
        "in_queue" : 57836,
        "util" : 96.17
      }
    ]
  }

Answer 1

如果你确定在第一个之前没有'{‘，在开头有'}’，我会用正则表达式来处理它(如果你有不同的格式，我可以进行调整)：

import re

pattern = re.compile(r"{.*}", re.DOTALL)
match = pattern.search(stdout)
print(match.group(0))

如果你不喜欢正则表达式，但是你仍然对字符串的结构有相同的假设，你可以这样做：

start = stdout.find('{')
stdout[start:] # it means from start to the end