python strings要请求，为什么用\ var \ \＆＃x27代替双引号？

Question

我正在与 valhalla 检索旅行持续时间。在文档中，发送请求的格式如下：

   {"sources":[{"lat":40.744014,"lon":-73.990508}],"targets":[{"lat":40.744014,"lon":-73.990508},{"lat":40.739735,"lon":-73.979713},{"lat":40.752522,"lon":-73.985015},{"lat":40.750117,"lon":-73.983704},{"lat":40.750552,"lon":-73.993519}],"costing":"pedestrian"}&id=ManyToMany_NYC_work_dinner

我正在独立创建源和目标，这是来源的代码：

'{"sources":[{"lat": 19.690742994833027, "lon": -99.1680363639107]'

目标来自大熊猫的系列：

<style type="text/css">
  .tg {
    border-collapse: collapse;
    border-spacing: 0;
  }
  
  .tg td {
    border-color: black;
    border-style: solid;
    border-width: 1px;
    font-family: Arial, sans-serif;
    font-size: 14px;
    overflow: hidden;
    padding: 10px 5px;
    word-break: normal;
  }
  
  .tg th {
    border-color: black;
    border-style: solid;
    border-width: 1px;
    font-family: Arial, sans-serif;
    font-size: 14px;
    font-weight: normal;
    overflow: hidden;
    padding: 10px 5px;
    word-break: normal;
  }
  
  .tg .tg-0pky {
    border-color: inherit;
    text-align: left;
    vertical-align: top
  }
  
  .tg .tg-0lax {
    text-align: left;
    vertical-align: top
  }
</style>
<table class="tg" style="undefined;table-layout: fixed; width: 433px">
  <colgroup>
    <col style="width: 91px">
    <col style="width: 342px">
  </colgroup>
  <thead>
    <tr>
      <th class="tg-0pky">Reference</th>
      <th class="tg-0pky">order_point</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td class="tg-0pky">1</td>
      <td class="tg-0pky">[19.690742994833027,-99.1680363639107]</td>
    </tr>
    <tr>
      <td class="tg-0lax">2</td>
      <td class="tg-0lax">[19.67109, -99.16845]</td>
    </tr>
    <tr>
      <td class="tg-0lax">3</td>
      <td class="tg-0lax">[19.684034594944944, -99.15103970155211]</td>
    </tr>
    <tr>
      <td class="tg-0lax">4</td>
      <td class="tg-0lax">[19.686485, -99.23003]</td>
    </tr>
    <tr>
      <td class="tg-0lax">5</td>
      <td class="tg-0lax">[19.718996, -99.13548]</td>
    </tr>
  </tbody>
</table>

And are turned into a list of dicts:

trgt_dicts = [{"lat": i[0], "lon": i[1]} for i in targets]

返回：

[{'lat': 19.690742994833027, 'lon': -99.1680363639107}, {'lat': 19.67109, 'lon': -99.16845}, {'lat': 19.684034594944944, 'lon': -99.15103970155211},  {'lat': 19.686485, 'lon': -99.23003}, {'lat': 19.718996, 'lon': -99.13548}]

所以，当我将所有东西放在一起时：

query = '{"sources":[{"lat": 'f'{source[0]}'', "lon": 'f'{source[1]}''], "targets": 'f'{trgt_dicts}'', "costing":"auto"}'

我得到的是：

'{"sources":[{"lat": 19.690742994833027, "lon": -99.1680363639107], "targets": [{\'lat\': 19.690742994833027, \'lon\': -99.1680363639107}, {\'lat\': 19.67109, \'lon\': -99.16845}, {\'lat\': 19.684034594944944, \'lon\': -99.15103970155211}, {\'lat\': 19.686485, \'lon\': -99.23003}, {\'lat\': 19.718996, \'lon\': -99.13548}], "costing":"auto"}'

检索和错误，我认为原因是 \'lon \'：我得到了而不是“ lon”：

我尝试使用json.dumps，以尝试获得其他问题中建议的正确格式。我还为源和目标创建了变量，并在使用F弦之后将它们放在一起：

qsource = '{"sources":[{"lat": 'f'{source[0]}'', "lon": 'f'{source[1]}''], "targets":'
qtrgt = ','.join(map(str, [trgt_dicts]))
query = qsource + qtrgt + ',"costing":"auto"}'

但是最后，无论如何，我最终都得到了这个 \'lon \'：

Answer 1

i think 您的意思是查询是字典，但是您正在创建一个字符串（通过附加一堆子字符串）。仔细观察您的语法：

query = '{"sources":[{"lat": 'f'{source[0]}'', "lon": 'f'{source[1]}''], "targets": 'f'{trgt_dicts}'', "costing":"auto"}'

如果我们将子字符串拆分以使其更清楚，这就是您所写的：

query = (
    '{"sources":[{"lat": '
    + f"{source[0]}"
    + ', "lon": '
    + f"{source[1]}"
    + '], "targets": '
    + f"{trgt_dicts}"
    + ', "costing":"auto"}'
)

老实说，这很奇怪。我认为你想要什么
喜欢：

query = {
    "sources": [
        {
            "lat": source[0],
            "lon": source[1],
        },
    ],
    "targets": trgt_dicts,
}

那给你一个python词典。如果您想json对它进行编码，您
可以使用json.dumps。假设您有：

>>> source
[40.744014, -73.990508]
>>> trgt_dicts
[
    {"lat": 40.744014, "lon": -73.990508},
    {"lat": 40.739735, "lon": -73.979713},
    {"lat": 40.752522, "lon": -73.985015},
    {"lat": 40.750117, "lon": -73.983704},
    {"lat": 40.750552, "lon": -73.993519},
]

这给了您：

>>> query = {
...     "sources": [
...         {
...             "lat": source[0],
...             "lon": source[1],
...         },
...     ],
...     "targets": trgt_dicts,
... }
>>> print(json.dumps(query, indent=2))
{
  "sources": [
    {
      "lat": 40.744014,
      "lon": -73.990508
    }
  ],
  "targets": [
    {
      "lat": 40.744014,
      "lon": -73.990508
    },
    {
      "lat": 40.739735,
      "lon": -73.979713
    },
    {
      "lat": 40.752522,
      "lon": -73.985015
    },
    {
      "lat": 40.750117,
      "lon": -73.983704
    },
    {
      "lat": 40.750552,
      "lon": -73.993519
    }
  ]
}