python - 如何通过将其索引视为键来展平包含列表的字典？

Question

我想压扁字典。字典可能包含列表。因此，在字典中展开列表时，应将列表索引视为其键。

我怎样才能做同样的事情？

我试过:

def flatten(d, parent_key='', sep='__'):
    items = []
    for k, v in d.items():
        new_key = parent_key + sep + k if parent_key else k
        if isinstance(v, collections.MutableMapping):
            items.extend(flatten(v, new_key, sep=sep).items())
        else:
            items.append((new_key, v))
    return dict(items)

这是扁平化字典但忽略列表。

我还尝试添加 if isinstance(v, list): , 但我不知道如何 append/extend在items .

data = {
    "checksum": "c540fcd985bf88c87e48c2bfa1df5498",
    "data": {
        "sampleMetrics": {
            "name": "DNA Library QC Metrics",
            "passQualityControl": "true",
            "metrics": [{
                "name": "CONTAMINATION_SCORE",
                "value": 1302,
                "LSL": 0,
                "USL": 3106,
                "UOM": "NA"
            }]
        }
    }
}
print flatten(data)

我得到的输出:

{
    'checksum': 'c540fcd985bf88c87e48c2bfa1df5498',
    'data__sampleMetrics__metrics': [{
        'LSL': 0,
        'USL': 3106,
        'name': 'CONTAMINATION_SCORE',
        'value': 1302,
        'UOM': 'NA'
    },{ 'demo': 11}],
    'data__sampleMetrics__name': 'DNA Library QC Metrics',
    'data__sampleMetrics__passQualityControl': 'true'
}

除了列表元素之外，它会展平其他东西。

预期输出:它也应该展平列表。(通过将列表索引视为键。)

{
    'checksum': 'c540fcd985bf88c87e48c2bfa1df5498',
    'data__sampleMetrics__metrics__0__LSL': 0,
    'data__sampleMetrics__metrics__0__USL': 3106,
    'data__sampleMetrics__metrics__0__name': 'CONTAMINATION_SCORE',
    'data__sampleMetrics__metrics__0__value': 1302,
    'data__sampleMetrics__metrics__0__UOM': 'NA',
    'data__sampleMetrics__metrics__1__demo': 11,
    'data__sampleMetrics__name': 'DNA Library QC Metrics',
    'data__sampleMetrics__passQualityControl': 'true'
}

如何通过将其索引作为键来展平包含列表的字典？

Answer 1

您还需要检查列表 - 它们不是 MutableMapings - 因此它们目前属于您的 else: 部分并按原样添加:

import collections
from itertools import chain 

def flatten(d, parent_key='', sep='__'):
    items = []
    for k, v in d.items():
        new_key = parent_key + sep + k if parent_key else k
        if isinstance(v, collections.MutableMapping):
            items.extend(flatten(v, new_key, sep=sep).items())
        elif isinstance(v, list):
            for idx, value in enumerate(v):
                items.extend(flatten(value, new_key + sep + str(idx), sep).items())
        else:
            items.append((new_key, v))
    return dict(items)

data = {
    "checksum": "c540fcd985bf88c87e48c2bfa1df5498",
    "data": {
        "sampleMetrics": {
            "name": "DNA Library QC Metrics",
            "passQualityControl": "true",
            "metrics": [{
                "name": "CONTAMINATION_SCORE",
                "value": 1302,
                "LSL": 0,
                "USL": 3106,
                "UOM": "NA"
            },{ 'demo': 11}]
        }
    }
}

print flatten(data) 

输出:

{'data__sampleMetrics__metrics__0__LSL': 0, 
 'checksum': 'c540fcd985bf88c87e48c2bfa1df5498', 
 'data__sampleMetrics__metrics__0__name': 'CONTAMINATION_SCORE', 
 'data__sampleMetrics__metrics__1__demo': 11, 
 'data__sampleMetrics__metrics__0__UOM': 'NA', 
 'data__sampleMetrics__metrics__0__USL': 3106, 
 'data__sampleMetrics__metrics__0__value': 1302, 
 'data__sampleMetrics__passQualityControl': 'true', 
 'data__sampleMetrics__name': 'DNA Library QC Metrics'}

---

要获得“排序”输出，您需要在 python 2.x 中使用 OrderedDict:

从集合中导入 OrderedDict

data = OrderedDict(sorted(flatten(data).items()))
print data 

输出:

OrderedDict([('checksum', 'c540fcd985bf88c87e48c2bfa1df5498'), 
             ('data__sampleMetrics__metrics__0__LSL', 0), 
             ('data__sampleMetrics__metrics__0__UOM', 'NA'), 
             ('data__sampleMetrics__metrics__0__USL', 3106), 
             ('data__sampleMetrics__metrics__0__name', 'CONTAMINATION_SCORE'), 
             ('data__sampleMetrics__metrics__0__value', 1302), 
             ('data__sampleMetrics__metrics__1__demo', 11), 
             ('data__sampleMetrics__name', 'DNA Library QC Metrics'), 
             ('data__sampleMetrics__passQualityControl', 'true')])