CODEWITHSUNDEEP
pythonrequest
Alberto Mario Castillo
Alberto Mario Castillo

Reputation: 9

Python strings to request, why is it replacing the double quotes with \'var\'?

I'm working with Valhalla to retrieve trips durations. In the documentation the format to send the request is as follows:

   {"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

I'm creating the source and the targets independently, this is the code for the source:

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

The targets come from a Pandas' series:

<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]

Which returns:

[{'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}]

So, when I put everything together:

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

What I get is this:

'{"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"}'

Which retrieves and error, and I think the reason is the \'lon\': I'm getting instead of "lon":

I have tried with json.dumps in an attempt to get the right format as suggested in other questions. I also created variables for the source and the targets and put them together after playing around with the f-string:

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

But at the end, no matter what, I end up with this \'lon\':

Upvotes: 0

Views: 55

Answers (1)

larsks
larsks

Reputation: 312440

I think you mean for query to be a dictionary, but you're creating a string (by appending a bunch of substrings). Take a closer look at your syntax:

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

If we split up the substrings to make it more clear, this is what you've written:

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

And honestly, that's just weird. I think what you want is something like:

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

That gives you a Python dictionary. If you want to JSON-encode it, you can use json.dumps. Assuming that you have:

>>> 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},
]

This gives you:

>>> 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
    }
  ]
}

Upvotes: 1

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