在python字典列表中仅选择最大值

Question

I have a list of dicts as follows:

[{"server":"8.8.8.8", 
  "domains":[{"google.com":[{"time":15, "serial":14}, {"time":78, "serial":14}]},
             {"intuit.com":[{"time":20, "serial":23}, {"time":91, "serial":18}]}
            ]
},
{"server":"8.8.4.4", 
 "domains":[{"google.com":[{"time":19, "serial":45}, {"time":92, "serial":76}]},
            {"intuit.com":[{"time":45, "serial":89}, {"time":93, "serial":74}]}
           ]
},
{"server":"206.67.222.222", 
 "domains":[{"google.com":[{"time":98, "serial":76}, {"time":64, "serial":54}]},
            {"intuit.com":[{"time":43, "serial":21}, {"time":65, "serial":59}]}
           ]
}]

How would I go about creating a structure where I select only the dict for each domain with the max serial number and when I have the same serial number, select the max time so that I am left with the following:

[{"server":"8.8.8.8", 
  "domains":[{"google.com":{"time":78, "serial":14}},
             {"intuit.com":{"time":20, "serial":23}}
            ]
 },
 {"server":"8.8.4.4", 
  "domains":[{"google.com":{"time":92, "serial":76}},
             {"intuit.com":{"time":45, "serial":89}}
            ]
 },
 {"server":"206.67.222.222", 
  "domains":[{"google.com":{"time":98, "serial":76}},
             {"intuit.com":{"time":65, "serial":59}}
            ]
 }]

Answer 1

Try this (d is your dict):

for item in d:
    for i in item["domains"]:
        for k, v in i.items():
            c = sorted([(j["time"], j["serial"]) for j in v], key=lambda x: (x[1], x[0]))
            i[k] = {"time": c[-1][0], "serial": c[-1][1]}

print d

Answer 2

The solution using built-in max() function:

import json

# l is your initial list of dicts
for item in l:
    for d in item['domains']:
        for k, v in d.items():
            # whether `serial` numbers are unique 
            has_uniq_serial = len(set([i['serial'] for i in v])) > 1
            d[k] = max(v, key=lambda o: o['serial']) if has_uniq_serial else max(v, key=lambda o: o['time'])

# `json.dumps` used for pretty printing of nested dicts
print(json.dumps(l, indent=4))

The output:

[
    {
        "server": "8.8.8.8",
        "domains": [
            {
                "google.com": {
                    "serial": 14,
                    "time": 78
                }
            },
            {
                "intuit.com": {
                    "serial": 23,
                    "time": 20
                }
            }
        ]
    },
    {
        "server": "8.8.4.4",
        "domains": [
            {
                "google.com": {
                    "serial": 76,
                    "time": 92
                }
            },
            {
                "intuit.com": {
                    "serial": 89,
                    "time": 45
                }
            }
        ]
    },
    {
        "server": "206.67.222.222",
        "domains": [
            {
                "google.com": {
                    "serial": 76,
                    "time": 98
                }
            },
            {
                "intuit.com": {
                    "serial": 59,
                    "time": 65
                }
            }
        ]
    }
]

Answer 3

You can sort your time-serial list for each domain by your requirement and get the first one, let variable data be your input list:

def domain_sorter(d):
    def compare(x, y):
        k = y['serial'] - x['serial']
        j = y['time'] - x['time']

        return k if k != 0 else j
    return sorted(d, cmp=compare)

def filter_domain(domain):
    for k, v in domain.items():
        return {
            k: domain_sorter(v)[0]
        }

print [{
    "server": e['server'],
    "domains": [filter_domain(domain) for domain in e['domains']]
} for e in data]