json file = 
    {
      "success": true,"terms": "https://curr
      "privacy": "https://cu
      "timestamp": 162764598
      "source": "USD","quotes": {
        "USDIMP": 0.722761,"USDINR": 74.398905,"USDIQD": 1458.90221
       
      }
    }

json 文件在上面。我从 json 中删除了很多值，因为它占用了太多空间。我的python代码在下面。

    import urllib.request,urllib.parse,urllib.error
    
    import json
    
    response = "http://api.currencylayer.com/live?access_key="
    
    api_key = "42141e*********************"
    parms = dict()
    
    
    
    parms['key'] = api_key
    url = response + urllib.parse.urlencode(parms)
    mh = urllib.request.urlopen(url)    
    source = mh.read().decode()
    
    data = json.loads(source)
    pydata = json.dumps(data,indent=2)
    
    print("which curreny do you want to convert USD to?")
    xm = input('>')
    print(f"Hoe many USD do you want to convert{xm}to")
    value = input('>')
    
    fetch = pydata["quotes"][0]["USD{xm}"]
    
    answer = fetch*value 
    
    print(fetch)
--------------------------------

这里是 输出 "fetch = pydata["quotes"][0]["USD{xm}"]
类型错误：字符串索引必须是整数"