就是现在网页的背景效果，是从网上抄的 需要把文件放到个js里面，然后在foolter里面引用。 代码如下, 本质是个IIFE !function () { function n(n, e, t) { return n.getAttribute(e) || t } function e(n) { return document.getElementsByTagName(n) } function t() { var t = e("script"), o = t.length, i = t[o - 1]; return { l: o, z: n(i, "zIndex", -1), o: n(i, "opacity", .5), c: n(i, "color", "0,0,0"), n: n(i, "count", 99) } } function o() { a = m.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth, c = m.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight } function i() {……

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the code in jupyter notebook refer to file pandas_demo.ipynb……

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the code in jupyter notebook the file numpy_demo.ipynb……

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How to install new package conda install xxx list env conda env list activate one env conda activate xx deactivate env conda deactivate ……

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python context manager use contextlib/yield @contextmanager def send_mail_context(): '''context manager with send_mail_context() ''' try: # 1 doing work BEFORE the code goes into with block print('before yield') server = smtplib.SMTP(SMTP_SERVERS[0], 25) # 2 yield back to with/caller yield server except Exception as e: print(e) finally: # 4. doing cleanup work server.quit() print('in finally') use class __enter__, __exit__ # 2 implement contextmanager with class class SMTPCT(object): ''' 1. override __enter__ __exit__ 2. in __enter__, return value ''' def __init__(self): self.smtp_server = None def __enter__(self): # 1 doing work BEFORE the code goes into with block print('in enter') self.smtp_server = smtplib.SMTP(SMTP_SERVERS[0], 25) # 2 return back to with/caller return self.smtp_server def __exit__(self, type, value, traceback): # 4. doing cleanup work print('in exit') self.smtp_server.quit() ……

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how to send mail in python #!/usr/bin/env python3 # -*- coding: utf-8 -*- # smtplib -> https://docs.python.org/3/library/smtplib.html import smtplib # contextlib -> https://docs.python.org/3/library/contextlib.html from contextlib import contextmanager # email -> https://docs.python.org/3/library/email.examples.html#email-examples from email import encoders from email.header import Header from email.mime.text import MIMEText from email.utils import parseaddr, formataddr SMTP_SERVERS = ['your smtp servers'] def _format_addr(s): ''' format the address ''' name, addr = parseaddr(s) return formataddr((Header(name, 'utf-8').encode(), addr)) def generate_mail(from_addr, to_addr, cc_addr, subject, body, mime_type='plain'): '''plain/text text/html ''' msg = MIMEText(body, mime_type, 'utf-8') msg['From'] = _format_addr(from_addr) msg['To'] = ",".join([_format_addr(x) for x in to_addr]) msg['Cc'] = ",".join([_format_addr(x) for x in cc_addr]) msg['Subject'] = Header(subject, 'utf-8').encode() return msg def send_mail(from_addr, to_addr, cc_addr, subject, body, mime_type='plain'): server = smtplib.SMTP(SMTP_SERVERS[0], 25) server.set_debuglevel(1) msg = generate_mail(from_addr, to_addr, cc_addr, subject, body, mime_type) server.sendmail(from_addr, to_addr + cc_addr, msg.as_string()) server.quit() # 1. to implement context manager, use decorator @contextmanager # and yield @contextmanager def send_mail_context(): '''context manager with send_mail_context() ''' try: # 1 doing work BEFORE the code goes into with block print('before yield') server = smtplib.……

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method resolution order #!/usr/bin/env python3 # -*- coding: utf-8 -*- # method resolution order # mro class A(object): def hello(self): print('class A says hello') class B(A): pass class C(A): # class variable BP_URL = 'https://xxxxx' def __init__(self): self.name = 'ok' @staticmethod def print_hello(name, age): ''' staticmethod cannot access any class or self variabel/method ''' pass @classmethod def say(cls): '''class method can access class level variable/method ''' print(cls.BP_URL) def hello(self): print('class C says hello') class D(C, B): pass if __name__ == '__main__': d = D() d.hello() # to print the mro of one class print(d.__class__.__mro__) ……

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dunder methods #!/usr/bin/env python3 # -*- coding: utf-8 -*- # double underscore variable/function # dunder class A(object): def __init__(self, number): self.number = number def __eq__(self, value): ''' a == b ''' return super().__eq__(value) def __ge__(self, value): ''' a >= b ''' return super().__ge__(value) def __gt__(self, value): ''' a > b ''' return super().__gt__(value) def __le__(self, value): ''' a < b ''' return super().__le__(value) def __ne__(self, value): ''' a != b ''' return super().__ne__(value) def __str__(self): '''print(a) ''' return super().__str__() def __repr__(self): return super().__repr__() def __len__(self): ''' len(a) ''' return self.number * 10 def __lt__(self, other): '''less than a < b ''' return self.number < other.number def __getattribute__(self, name): ''' print(a[the_key]) ''' return super().__getattribute__(name) def __setattr__(self, name, value): ''' a[the_key] = 5 ''' return super().__setattr__(name, value) def __delattr__(self, name): ''' delete a['the_key'] ''' return super().__delattr__(name) if __name__ == '__main__': ''' ''' # a = A(5) # b = A(6) # print(a < b) # print(len(a)) # a['b'] = 10 # c = a['c'] pass ……

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Too many or too few labels 如果在使用darknet过程中，遇到这个错误，很可能你的labels文件里面的label定义的有问题 label之间要不包含 label 名字不要出现在train/test的路径中 所以如果定义一个label是a, 很可能就不行，train里面包含a，所以还是定义的稍微长点。……

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无参装饰器 #1. decorator without arguments def log_time_always(func): @wraps(func) def wrapped(*args, **kwargs): #1. get current time t1 = datetime.now() #2. run the function func(*args, **kwargs) #3. get current time t2 = datetime.now() print(f'in {func.__name__}, it took {t2-t1}') return wrapped 带参数的装饰器 #2. decorator with arguments, flag is True or False def log_time(flag): def wrapper(func): @wraps(func) def wrapped(*args, **kwargs): # if flag is true, we need to log the time if flag: #1. get current time t1 = datetime.now() #2. run the function func(*args, **kwargs) #3. get current time t2 = datetime.now() print(f'in {func.__name__}, it took {t2-t1}') else: func(*args, **kwargs) return wrapped return wrapper 本质 装饰器需要能够处理一个函数 无参 @decorator_1 def f(): pass 等同于 def f(): pass f =……

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