如何在列表理解中使用 if else？

Question

我有一个词典列表：

data = [{'end_time': 1628565660, 'show': 'mad.men', 'cost': 0.0023123688 }, 
    {'end_time': 1628565780, 'show': 'the.sopranos', 'cost': 0.0023123688},
    {'end_time': 1628565780, 'show': 'breaking.bad', 'cost': 1.0667859907}]

这里我有一个嵌套字典的列表：

[{'mad.men': {'timestamp': '1628566560', 'cost': 0}, 
  'breaking.bad': {'timestamp': '1628566560', 'cost': 0}, 
  'the.sopranos': {'timestamp': '1628566560', 'cost': 0}}, 
 {'mad.men': {'timestamp': '1628566620', 'cost': 0}, 
  'breaking.bad': {'timestamp': '1628566620', 'cost': 0}, 
  'the.sopranos': {'timestamp': '1628566620', 'cost': 0}}, 
 {'mad.men': {'timestamp': '1628566680', 'cost': 0}, 
  'breaking.bad': {'timestamp': '1628566680', 'cost': 0}, 
  'the.sopranos': {'timestamp': '1628566680', 'cost': 0}}, 
 {'mad.men': {'timestamp': '1628566740', 'cost': 0}, 
  'breaking.bad': {'timestamp': '1628566740', 'cost': 0}, 
  'the.sopranos': {'timestamp': '1628566740', 'cost': 0}}, 
 {'mad.men': {'timestamp': '1628566800', 'cost': 0}, 
  'breaking.bad': {'timestamp': '1628566800', 'cost': 0}, 
  'the.sopranos': {'timestamp': '1628566800', 'cost': 0}}, 
 {'mad.men': {'timestamp': '1628566860', 'cost': 0}, 
  'breaking.bad': {'timestamp': '1628566860', 'cost': 0}, 
  'the.sopranos': {'timestamp': '1628566860', 'cost': 0}}]

我在这里想要实现的是遍历我的 data 列表，并且 results 列表与节目和时间戳相匹配，这样我就可以用刚刚显示的数据替换该时间戳内的成本进来了。

例如，如果数据有： 'the.sopranos': {'timestamp': '1628566860', 'cost': 5.00 并且结果列表与时间戳匹配，结果中的这个值：

'the.sopranos': {'timestamp': '1628566560', 'cost': 0}

转换为

'the.sopranos': {'timestamp': '1628566560', 'cost': 5.00}

这是我迄今为止尝试过的：

for item in data:
dt_object = datetime.datetime.fromtimestamp(item['end_time'] / 1000.0).replace(second=0, microsecond=0).strftime('%s')
for k, v in [(k, v)  for x in results for (k, v) in x.items() if  k == item['show'] and  dt_object == v['timestamp']]:
    print(k,v)

但它只打印 nothing.How 我可以在列表理解中实现 if – else 吗？或者我的问题的另一种选择

Answer 1

在这种情况下我不会使用列表理解，而是使用 for 循环。

for item in data:
    show = item['show']
    timestamp = item['end_time']
    cost = item['cost']
    for result in results:
        info = result[show]
        if info['timestamp'] != timestamp:
            continue
        result['cost'] = cost
print(results)

或者如果您想要更短的版本：

for item in data:
    for result in results:
        info = result[item['show']]
        if info['timestamp'] != item['end_time']:
            continue
        result['cost'] = item['cost']
print(results)

根据您提供的信息，data 中的超时与 results

中的超时不匹配

Answer 2

results = [dict((key,d[key]) for d in data for key in d) for data in [[{list(results[index//len(results)].keys())[index%3]:{'timestamp':results[index//len(results)][list(results[index//len(results)].keys())[index%3]]['timestamp'],'cost':5}} if flag else {list(results[index//len(results)].keys())[index%3]:{'timestamp':results[index//len(results)][list(results[index//len(results)].keys())[index%3]]['timestamp'],'cost':results[index//len(results)][list(results[index//len(results)].keys())[index%3]]['cost']}} for index,flag in enumerate(flags)][f_i:f_i+len(results[0])] for f_i in range(0, len([{list(results[index//len(results)].keys())[index%3]:{'timestamp':results[index//len(results)][list(results[index//len(results)].keys())[index%3]]['timestamp'],'cost':5}} if flag else {list(results[index//len(results)].keys())[index%3]:{'timestamp':results[index//len(results)][list(results[index//len(results)].keys())[index%3]]['timestamp'],'cost':results[index//len(results)][list(results[index//len(results)].keys())[index%3]]['cost']}} for index,flag in enumerate(flags)]), len(results[0]))]]

如何在列表理解中使用 if else？

How to utilize if else in a list comprehension?

python

dictionary

list-comprehension

list

python-3.x