Question

我希望从下面的所有3个列表中拉出“最高”。我不确定如何进行。

[  
   {  
      'timestamp':'2019-04-09T23:41:00.000Z',
      'symbol':'XBTUSD',
      'open':5189.5,
      'high':5190,
      'low':5189,
      'close':5190,
      'trades':14,
      'volume':1246,
      'vwap':5189.4136,
      'lastSize':480,
      'turnover':24010476,
      'homeNotional':0.24010476,
      'foreignNotional':1246
   },
   {  
      'timestamp':'2019-04-09T23:40:00.000Z',
      'symbol':'XBTUSD',
      'open':5190,
      'high':5190,
      'low':5189.5,
      'close':5189.5,
      'trades':4,
      'volume':540,
      'vwap':5189.9523,
      'lastSize':20,
      'turnover':10404800,
      'homeNotional':0.104048,
      'foreignNotional':540
   },
   {  
      'timestamp':'2019-04-09T23:39:00.000Z',
      'symbol':'XBTUSD',
      'open':5197.5,
      'high':5195.5,
      'low':5187,
      'close':5190,
      'trades':56,
      'volume':24286,
      'vwap':5189.6829,
      'lastSize':1058,
      'turnover':467970327,
      'homeNotional':4.67970327,
      'foreignNotional':24286
   }
]

我试图简单地使用high = [0:]["high"]-但这会返回

 TypeError: list indices must be integers or slices, not str

什么是将每个列表中的所有3个“高”都包含在内的适当命令？对于这种情况，它应该返回5190, 5190, 5195.5。

Answer 1

使用列表理解：[ x['high'] for x in data ] 如果数据是您在原始帖子中发布的数组。

Answer 2

我认为下面的答案会有所帮助

我已将您的列表分配给listofDict，并且我正在使用for循环遍历所有列表元素。

由于listofDict元素是 dict 类型，因此我正在使用 key 提取 value 。

此处键为高

listofDict=[  
   {  
      'timestamp':'2019-04-09T23:41:00.000Z',
      'symbol':'XBTUSD',
      'open':5189.5,
      'high':5190,
      'low':5189,
      'close':5190,
      'trades':14,
      'volume':1246,
      'vwap':5189.4136,
      'lastSize':480,
      'turnover':24010476,
      'homeNotional':0.24010476,
      'foreignNotional':1246
   },
   {  
      'timestamp':'2019-04-09T23:40:00.000Z',
      'symbol':'XBTUSD',
      'open':5190,
      'high':5190,
      'low':5189.5,
      'close':5189.5,
      'trades':4,
      'volume':540,
      'vwap':5189.9523,
      'lastSize':20,
      'turnover':10404800,
      'homeNotional':0.104048,
      'foreignNotional':540
   },
   {  
      'timestamp':'2019-04-09T23:39:00.000Z',
      'symbol':'XBTUSD',
      'open':5197.5,
      'high':5195.5,
      'low':5187,
      'close':5190,
      'trades':56,
      'volume':24286,
      'vwap':5189.6829,
      'lastSize':1058,
      'turnover':467970327,
      'homeNotional':4.67970327,
      'foreignNotional':24286
   }
]


for l in listofDict:
   print (l['high'])

Answer 3

您可以使用pandas并转换为dataframe /表，然后可以获得df["high"]。

如果仅需要两个值，则可以执行df['high'][:2]。这与您尝试过的类似。

import pandas as pd

data = [  
   {  
      'timestamp':'2019-04-09T23:41:00.000Z',
      'symbol':'XBTUSD',
      'open':5189.5,
      'high':5190,
      'low':5189,
      'close':5190,
      'trades':14,
      'volume':1246,
      'vwap':5189.4136,
      'lastSize':480,
      'turnover':24010476,
      'homeNotional':0.24010476,
      'foreignNotional':1246
   },
   {  
      'timestamp':'2019-04-09T23:40:00.000Z',
      'symbol':'XBTUSD',
      'open':5190,
      'high':5190,
      'low':5189.5,
      'close':5189.5,
      'trades':4,
      'volume':540,
      'vwap':5189.9523,
      'lastSize':20,
      'turnover':10404800,
      'homeNotional':0.104048,
      'foreignNotional':540
   },
   {  
      'timestamp':'2019-04-09T23:39:00.000Z',
      'symbol':'XBTUSD',
      'open':5197.5,
      'high':5195.5,
      'low':5187,
      'close':5190,
      'trades':56,
      'volume':24286,
      'vwap':5189.6829,
      'lastSize':1058,
      'turnover':467970327,
      'homeNotional':4.67970327,
      'foreignNotional':24286
   }
]

df = pd.DataFrame(data)

print(df['high'].to_list())

[5190.0, 5190.0, 5195.5]

如何从Python字典列表中提取数据

3 个答案: