在python中显示零时合并列表

Question

我创建了一个Django查询集，它可以计算值，但不幸的是，它没有显示0值。因此，我想合并我的两个列表，就像SQL中的left join一样。我显示我的输入和期望的输出。你知道吗

输入1（Django查询1）：

我这样打印出来：

for i in query_1:
     print (i['day'], i['count_1'])  

2018-01-17 00:00:00+01:00 49
2018-01-16 00:00:00+01:00 139
2018-01-15 00:00:00+01:00 144
2018-01-14 00:00:00+01:00 142
2018-01-13 00:00:00+01:00 141
2018-01-12 00:00:00+01:00 144
2018-01-11 00:00:00+01:00 145
2018-01-10 00:00:00+01:00 95

输入2（Django查询2）：

我这样打印出来：

    for i in query_2:
         print (i['day'], i['count_2'])  

   2018-01-17 00:00:00+01:00 2
   2018-01-16 00:00:00+01:00 6
   2018-01-14 00:00:00+01:00 2
   2018-01-13 00:00:00+01:00 4

我想要的输出是：

2018-01-17 00:00:00+01:00 49  2
2018-01-16 00:00:00+01:00 139 6
2018-01-15 00:00:00+01:00 144 0
2018-01-14 00:00:00+01:00 142 2
2018-01-13 00:00:00+01:00 141 4
2018-01-12 00:00:00+01:00 144 0
2018-01-11 00:00:00+01:00 145 0
2018-01-10 00:00:00+01:00 95  0 

我试过了，但失败了：

for a, b in zip (query_1, query_2)
    if a['day'] == b['day']:
       print (a['count_2']) #It prints only the result of query_2 not both :(
    else:
       print ('0') 

Answer 1

query_1 = [{'day': '2018-01-17 00:00:00+01:00','count_1': '49'},
           {'day': '2018-01-16 00:00:00+01:00','count_1': '139'},
           {'day': '2018-01-15 00:00:00+01:00','count_1': '144'},
           {'day': '2018-01-14 00:00:00+01:00','count_1': '142'}]


query_2 = [{'day': '2018-01-17 00:00:00+01:00','count_2': '2'},
           {'day': '2018-01-16 00:00:00+01:00','count_2': '6'},
           {'day': '2018-01-15 00:00:00+03:00','count_2': '2'},
           {'day': '2018-01-14 00:00:00+01:00','count_2': '4'}]

for a, b in zip(query_1, query_2):
    if a['day'] == b['day']:
        print a['day'] + " " + a['count_1'] + " " + b['count_2']
    else:
        print a['day'] + " " + a['count_1'] + " 0"

输出：

2018-01-17 00:00:00+01:00 49 2
2018-01-16 00:00:00+01:00 139 6
2018-01-15 00:00:00+01:00 144 0
2018-01-14 00:00:00+01:00 142 4

Answer 2

我试着用熊猫，我认为这是最简单的方法。我的方法步骤是：

1，将对象转换为数据帧

• pd_query_1 = pd.DataFrame.from_records(query_1)

• pd_query_2 = pd.DataFrame.from_records(query_2)

2，左连接两个查询

• result = (pd.merge(pd_query_1, pd_query_2, how='left', on=['day', 'day'])).fillna(0)

Answer 3

new_data = [ i['day'] + ' ' + str(i['count_1']) for i in query_1]  
new_data.extend([ i['day'] + ' ' + str(i['count_1']) for i in query_2])
local_dict = {}
for values in new_data:
    date, time, val = values.split()
    if date in local_dict:
        new_value = local_dict[date]
        local_dict[date] = new_value.replace(new_value[-1],val)
    else:
        local_dict.setdefault(date,values+ (' %s' % '0'))
print(local_dict.values())
>>>
["2018-01-17 00:00:00+01:00 49  2",
"2018-01-16 00:00:00+01:00 139 6",
"2018-01-15 00:00:00+01:00 144 0",
"2018-01-14 00:00:00+01:00 142 2",
"2018-01-13 00:00:00+01:00 141 4",
"2018-01-12 00:00:00+01:00 144 0",
"2018-01-11 00:00:00+01:00 145 0",
"2018-01-10 00:00:00+01:00 95  0"]