学习Python的列表生成器以及Map-Reduce

最近写了很多接口，需要反复处理 json 数据，抽离数据，重组格式。

花时间研究了一些 Python 的列表生成式，以及更高级的 Map/Reduce，并给大家做了一次分享，记录一下分享过程中写下的代码。

示例数据

from functools import reduce

datas = [
    {
        "date": "22日星期四",
        "sunrise": "06:17",
        "high": "高温 17.0℃",
        "low": "低温 1.0℃",
        "sunset": "18:27",
        "aqi": 98,
        "fx": "西南风",
        "fl": "<3级",
        "type": "晴",
        "notice": "愿你拥有比阳光明媚的心情"
    },
    {
        "date": "23日星期五",
        "sunrise": "06:16",
        "high": "高温 18.0℃",
        "low": "低温 5.0℃",
        "sunset": "18:28",
        "aqi": 118,
        "fx": "无持续风向",
        "fl": "<3级",
        "type": "多云",
        "notice": "阴晴之间，谨防紫外线侵扰"
    },
    {
        "date": "24日星期六",
        "sunrise": "06:14",
        "high": "高温 21.0℃",
        "low": "低温 7.0℃",
        "sunset": "18:29",
        "aqi": 52,
        "fx": "西南风",
        "fl": "<3级",
        "type": "晴",
        "notice": "愿你拥有比阳光明媚的心情"
    },
    {
        "date": "25日星期日",
        "sunrise": "06:13",
        "high": "高温 22.0℃",
        "low": "低温 7.0℃",
        "sunset": "18:30",
        "aqi": 71,
        "fx": "西南风",
        "fl": "<3级",
        "type": "晴",
        "notice": "愿你拥有比阳光明媚的心情"
    },
    {
        "date": "26日星期一",
        "sunrise": "06:11",
        "high": "高温 21.0℃",
        "low": "低温 8.0℃",
        "sunset": "18:31",
        "aqi": 97,
        "fx": "西南风",
        "fl": "<3级",
        "type": "多云",
        "notice": "阴晴之间，谨防紫外线侵扰"
    }
]


def add(x):
    return x + 'Z'


def sum(x, y):
    return x + y

列表生成式

if __name__ == '__main__':
    zz = []
    for data in datas:
        zz.append(data['date'] + data['high'] + data['low'])
    print(zz)

    p = 9
    a = 10
    zz = p if p > a else a
    print(zz)

    zz = [data['date'] + data['high'] + data['low'] for data in datas if data["aqi"] > 90]
    print(zz)

    zz = ['不好' if data["aqi"] > 90 else '不好' for data in datas]
    print(zz)

    zz = [{data['date']: data['high']} for data in datas]
    print(zz)

    # zz = {data['date']: data['high'],data['sunrise']: data['sunset'] for data in datas}
    # print(zz)

Map 与 Reduce

# MAP
list_a = ['A', 'B', 'C']

list_b = [1, 2, 3]
# map --  ['A+','B+','C+']
# reduce -- D= 'A+'+'B+'+'C+'

zz = list(map(add, list_a))
print(zz)

zz = reduce(sum, list_b, 6)
print(zz)

zz = list(map(lambda x: x + 'Z', list_a))
print(zz)

zz = reduce(lambda x, y: x + y, list_b, 6)
print(zz)

zz = list(
    map(lambda x: {x['date']: x['fx'], x['aqi']: x['sunset'], 'status': '好天气' if x['aqi'] < 90 else '坏天气'},
        datas))
print(zz)

zz = []
for x in datas:
    d = {x['date']: x['fx'], x['aqi']: x['sunset']}
    if x['aqi'] < 90:
        d['status'] = '好天气'
    else:
        d['status'] = '坏天气'
    zz.append(d)
print(zz)

zz = reduce(lambda d, k: {**d, **{k['date']: k['fx'], k['sunrise']: k['sunset']}}, datas, {})
print(zz)

a = {'22日星期四': '西南风', 98: '18:27', 'status1': '坏天气'}
b = {'23日星期五': '无持续风向', 118: '18:28', 'status2': '天气'}

print(a.update(b))
print({**a, **b})

datas = [(3, 5), (6, 8), (1, 9), (4, 8)]

zz = reduce(lambda d, k: (d[0] + k[0], d[1] + k[1]), datas, (0, 0))
print(zz)