如何从 Python 中的复杂列表中提取元素

Question

I have a list like this:

ls = {
    'info': {
        'id': '237371250',
        'market': 'BCH-PERP',
        'future': 'BCH-PERP',
        'side': 'sell',
        'type': 'stop',
        'orderPrice': None,
        'triggerPrice': '104.2',
        'size': '83.33',
        'status': 'open',
        'createdAt': '2022-07-16T12:25:02.288247+00:00',
        'triggeredAt': None,
        'orderId': None,
        'error': None,
        'reduceOnly': True,
        'trailValue': None,
        'trailStart': None,
        'cancelledAt': None,
        'cancelReason': None,
        'retryUntilFilled': True,
        'orderType': 'market',
        'filledSize': '0.0',
        'avgFillPrice': None},
    'id': '237371250',
    'clientOrderId': None,
    'timestamp': 1657974302288,
    'datetime': '2022-07-16T12:25:02.288Z',
    'lastTradeTimestamp': None,
    'symbol': 'BCH/USD:USD',
    'type': 'stop',
    'timeInForce': None,
    'postOnly': None,
    'reduceOnly': True,
    'side': 'sell',
    'price': 104.2,
    'stopPrice': 104.2,
    'amount': 83.33,
    'cost': 0.0,
    'average': None,
    'filled': 0.0,
    'remaining': 83.33,
    'status': 'open',
    'fee': None,
    'trades': [],
    'fees': []}

I would like to extract the 'triggerPrice' value of 104.2 from it. How would I go about doing that?

I have tried ls['triggerPrice'] but that returns an error.

Any information about what kind of data structure this is and how to access its elements would be gratefully received.

Answer 1

This datastructure is called a dictionary ( dict ) and it works the same way as JSON, just the types are Pythonic.

Eg: A typical JSON file would be like this

{
    "id": 2,
    "name": null,
    "is_allowed": false
}

in python it would be something like this

{
    "id": 2,
    "name": None,
    "is_allowed": False,
}

As you can see, only the types are changed.

To access elements in a dictionary, you just put the name of the dict, eg ls , then lookup a value in the dict with a key: ls["id"]

The solution to your question will be ls["info"]["triggerPrice"]