title: How to read a JSON result in Python3
body: <p>I'm trying to calculate the exchange from US Dolar to Brazilian Reais. </p>
  
  <p>I found an REST API from brazilian central bank. </p>
  
  <p>My Python code is receive the API return in JSON format, like that:</p>
  
  <p>{'@odata.context': '<a href="https://was-p.bcnet.bcb.gov.br/olinda/servico/PTAX/versao/v1/odata" rel="nofollow noreferrer">https://was-p.bcnet.bcb.gov.br/olinda/servico/PTAX/versao/v1/odata</a>$metadata#_CotacaoDolarDia(cotacaoVenda)', 'value': [{'cotacaoVenda': 3.8344}]}</p>
  
  <p>In my code I could isolate this part of resulte "[{'cotacaoVenda': 3.8344}]", but I can't isolate only the value "3.8344".</p>
  
  <p>Follow my code: </p>
  
  <pre><code># Cotação do Dólar V.01
  
  import json
  import requests
  
  r = requests.get("https://olinda.bcb.gov.br/olinda/servico/PTAX/versao/v1/odata/CotacaoDolarDia(dataCotacao=@dataCotacao)?@dataCotacao='03-15-2019'&amp;$top=1&amp;$format=json&amp;$select=cotacaoVenda")
  
  if r.status_code == 200:
      cotacao = json.loads(r.content)
      print(cotacao['value'])
  </code></pre>
  
  <p>Any idea how can I isolate only the "3.8344" contained in JSON return?</p>
  
  <p>Thank you</p>