copy
直接賦值時，新變數只是前一變數的參考，新變數改變了，前一變數也會改變，
淺拷貝只拷貝父物件，不拷貝子物件，如下offline_json_record的time為父物件，tags為子物件，任意一個變數中的子物件改變了，其他變數中的子物件也會同時改變，
深拷貝完全拷貝了父物件與子物件，變數中的父、子物件改變后，與被拷貝的變數相互不影響，如下offline_json_record，r1，r2相互不影響，
import copy
offline_json_record = {
"measurement": 'offline_device',
"time": '',
"tags": {
'region': ''
},
"fields": {
'value': 0
}
}
r1 = copy.deepcopy(offline_json_record)
r2 = copy.deepcopy(offline_json_record)
參考：
https://www.runoob.com/w3cnote/python-understanding-dict-copy-shallow-or-deep.html
當前年月日
>>> import datetime >>> datetime.datetime.now().year 2020 >>> datetime.datetime.now().month 10 >>> datetime.datetime.now().day
8
參考：
https://www.runoob.com/python/python-date-time.html
https://blog.csdn.net/hanyuyang19940104/article/details/84069720
filter
offline_list = list(filter(lambda r: r['status'] == "OFFLINE", all_list))
# 等同于
def is_offline(record):
return record['status'] == "OFFLINE"
offline_list = list(filter(is_offline, all_list))
python ** 冪次方
>>> 5**2 25
>>> 1e-02 0.01
>>> 10e-03 0.01
>>> 2e4 20000.0
python內置函式:
https://blog.csdn.net/weixin_30332241/article/details/97496902?utm_medium=distribute.pc_aggpage_search_result.none-task-blog-2~all~sobaiduend~default-1-97496902.nonecase&utm_term=python%E6%80%8E%E4%B9%88%E8%A1%A8%E7%A4%BA10%E7%9A%84n%E6%AC%A1%E6%96%B9&spm=1000.2123.3001.4430
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標籤：Python