## 通知设置新通知

python李魔佛 发表了文章 • 0 个评论 • 187 次浏览 • 2019-07-11 09:43 • 来自相关话题

代码如下：
from scrapy.selector import Selector

def get_response_callback(content):
txt = str(content,encoding='utf-8')
resp = Selector(text=txt)
title = resp.xpath('//title/text()').extract_first()
print(title)

@defer.inlineCallbacks
url = 'http://www.baidu.com'
d=getPage(url.encode('utf-8'))
yield d

def done():
reactor.stop()

def done1(*args,**kwargs):
reactor.stop()

for i in range(4):

reactor.run()
上面的代码是无法停止的，如果使用的是

done函数的定义是没有参数的。

而使用另一个done函数带参数的done(*args,**kwargs)
是可以正常退出的，done里面写了reactor.stop() 函数

原创文章
转载请注明出处：
http://30daydo.com/article/509
查看全部
代码如下：

	from scrapy.selector import Selector

def get_response_callback(content):
txt = str(content,encoding='utf-8')
resp = Selector(text=txt)
title = resp.xpath('//title/text()').extract_first()
print(title)

@defer.inlineCallbacks
url = 'http://www.baidu.com'
d=getPage(url.encode('utf-8'))
yield d

def done():
reactor.stop()

def done1(*args,**kwargs):
reactor.stop()

for i in range(4):

reactor.run()

上面的代码是无法停止的，如果使用的是

done函数的定义是没有参数的。

而使用另一个done函数带参数的done(*args,**kwargs)
是可以正常退出的，done里面写了reactor.stop() 函数

原创文章
转载请注明出处：
http://30daydo.com/article/509

#### numpy indices的用法

量化交易李魔佛 发表了文章 • 0 个评论 • 199 次浏览 • 2019-07-08 17:58 • 来自相关话题

Suppose you have a matrix M whose (i,j)-th element equals

M_ij = 2*i + 3*j
One way to define this matrix would be

i, j = np.indices((2,3))
M = 2*i + 3*j
which yields

array([[0, 3, 6],
[2, 5, 8]])
In other words, np.indices returns arrays which can be used as indices. The elements in i indicate the row index:

In [12]: i
Out[12]:
array([[0, 0, 0],
[1, 1, 1]])
The elements in j indicate the column index:

In [13]: j
Out[13]:
array([[0, 1, 2],
[0, 1, 2]])
上面是Stack Overflow的解释。 翻译一下：

np.indices((2,3))

返回的是一个行列的索引，然后可以用这个索引快速的创建二维数据。

比如我要画一个圆：
img = np.zeros((400,400))
ir,ic = np.indices(img.shape)
circle = (ir-135)**2+(ic-150)**2 < 30**2 # 半径30，圆心在135,150
img[circle]=1

img现在就是一个圆啦
查看全部
Suppose you have a matrix M whose (i,j)-th element equals

M_ij = 2*i + 3*j
One way to define this matrix would be

i, j = np.indices((2,3))
M = 2*i + 3*j
which yields

array([[0, 3, 6],
[2, 5, 8]])
In other words, np.indices returns arrays which can be used as indices. The elements in i indicate the row index:

In [12]: i
Out[12]:
array([[0, 0, 0],
[1, 1, 1]])
The elements in j indicate the column index:

In [13]: j
Out[13]:
array([[0, 1, 2],
[0, 1, 2]])

上面是Stack Overflow的解释。 翻译一下：

np.indices((2,3))

返回的是一个行列的索引，然后可以用这个索引快速的创建二维数据。

比如我要画一个圆：
img = np.zeros((400,400))
ir,ic = np.indices(img.shape)
circle = (ir-135)**2+(ic-150)**2 < 30**2 # 半径30，圆心在135,150
img[circle]=1

img现在就是一个圆啦

#### cv2 distanceTransform函数的用法 python

python李魔佛 发表了文章 • 0 个评论 • 496 次浏览 • 2019-07-08 15:35 • 来自相关话题

distanceTransform
Calculates the distance to the closest zero pixel for each pixel of the source image.

Python: cv2.distanceTransform(src, distanceType, maskSize[, dst]) → dst

Parameters:
src – 8-bit, single-channel (binary) source image.
dst – Output image with calculated distances. It is a 32-bit floating-point, single-channel image of the same size as src .
distanceType – Type of distance. It can be CV_DIST_L1, CV_DIST_L2 , or CV_DIST_C .
maskSize – Size of the distance transform mask. It can be 3, 5, or CV_DIST_MASK_PRECISE (the latter option is only supported by the first function). In case of the CV_DIST_L1 or CV_DIST_C distance type, the parameter is forced to 3 because a 3\times 3 mask gives the same result as 5\times 5 or any larger aperture.
labels – Optional output 2D array of labels (the discrete Voronoi diagram). It has the type CV_32SC1 and the same size as src . See the details below.
labelType – Type of the label array to build. If labelType==DIST_LABEL_CCOMP then each connected component of zeros in src (as well as all the non-zero pixels closest to the connected component) will be assigned the same label. If labelType==DIST_LABEL_PIXEL then each zero pixel (and all the non-zero pixels closest to it) gets its own label.
The functions distanceTransform calculate the approximate or precise distance from every binary image pixel to the nearest zero pixel. For zero image pixels, the distance will obviously be zero.

When maskSize == CV_DIST_MASK_PRECISE and distanceType == CV_DIST_L2 , the function runs the algorithm described in [Felzenszwalb04]. This algorithm is parallelized with the TBB library.

In other cases, the algorithm [Borgefors86] is used. This means that for a pixel the function finds the shortest path to the nearest zero pixel consisting of basic shifts: horizontal, vertical, diagonal, or knight’s move (the latest is available for a 5\times 5 mask). The overall distance is calculated as a sum of these basic distances. Since the distance function should be symmetric, all of the horizontal and vertical shifts must have the same cost (denoted as a ), all the diagonal shifts must have the same cost (denoted as b ), and all knight’s moves must have the same cost (denoted as c ). For the CV_DIST_C and CV_DIST_L1 types, the distance is calculated precisely, whereas for CV_DIST_L2 (Euclidean distance) the distance can be calculated only with a relative error (a 5\times 5 mask gives more accurate results). For a,b , and c , OpenCV uses the values suggested in the original paper:

CV_DIST_C (3\times 3) a = 1, b = 1
CV_DIST_L1 (3\times 3) a = 1, b = 2
CV_DIST_L2 (3\times 3) a=0.955, b=1.3693
CV_DIST_L2 (5\times 5) a=1, b=1.4, c=2.1969
Typically, for a fast, coarse distance estimation CV_DIST_L2, a 3\times 3 mask is used. For a more accurate distance estimation CV_DIST_L2 , a 5\times 5 mask or the precise algorithm is used. Note that both the precise and the approximate algorithms are linear on the number of pixels.

The second variant of the function does not only compute the minimum distance for each pixel (x, y) but also identifies the nearest connected component consisting of zero pixels (labelType==DIST_LABEL_CCOMP) or the nearest zero pixel (labelType==DIST_LABEL_PIXEL). Index of the component/pixel is stored in \texttt{labels}(x, y) . When labelType==DIST_LABEL_CCOMP, the function automatically finds connected components of zero pixels in the input image and marks them with distinct labels. When labelType==DIST_LABEL_CCOMP, the function scans through the input image and marks all the zero pixels with distinct labels.

In this mode, the complexity is still linear. That is, the function provides a very fast way to compute the Voronoi diagram for a binary image. Currently, the second variant can use only the approximate distance transform algorithm, i.e. maskSize=CV_DIST_MASK_PRECISE is not supported yet.

Note
An example on using the distance transform can be found at opencv_source_code/samples/cpp/distrans.cpp
(Python) An example on using the distance transform can be found at opencv_source/samples/python2/distrans.py

查看全部
distanceTransform
Calculates the distance to the closest zero pixel for each pixel of the source image.

Python: cv2.distanceTransform(src, distanceType, maskSize[, dst]) → dst

Python: cv.DistTransform(src, dst, distance_type=CV_DIST_L2, mask_size=3, mask=None, labels=None) → None

Parameters:
src – 8-bit, single-channel (binary) source image.
dst – Output image with calculated distances. It is a 32-bit floating-point, single-channel image of the same size as src .

distanceType – Type of distance. It can be CV_DIST_L1, CV_DIST_L2 , or CV_DIST_C .
maskSize – Size of the distance transform mask. It can be 3, 5, or CV_DIST_MASK_PRECISE (the latter option is only supported by the first function). In case of the CV_DIST_L1 or CV_DIST_C distance type, the parameter is forced to 3 because a  3\times 3 mask gives the same result as  5\times 5 or any larger aperture.

labels – Optional output 2D array of labels (the discrete Voronoi diagram). It has the type CV_32SC1 and the same size as src . See the details below.

labelType – Type of the label array to build. If labelType==DIST_LABEL_CCOMP then each connected component of zeros in src (as well as all the non-zero pixels closest to the connected component) will be assigned the same label. If labelType==DIST_LABEL_PIXEL then each zero pixel (and all the non-zero pixels closest to it) gets its own label.
The functions distanceTransform calculate the approximate or precise distance from every binary image pixel to the nearest zero pixel. For zero image pixels, the distance will obviously be zero.



When maskSize == CV_DIST_MASK_PRECISE and distanceType == CV_DIST_L2 , the function runs the algorithm described in [Felzenszwalb04]. This algorithm is parallelized with the TBB library.

In other cases, the algorithm [Borgefors86] is used. This means that for a pixel the function finds the shortest path to the nearest zero pixel consisting of basic shifts: horizontal, vertical, diagonal, or knight’s move (the latest is available for a 5\times 5 mask). The overall distance is calculated as a sum of these basic distances. Since the distance function should be symmetric, all of the horizontal and vertical shifts must have the same cost (denoted as a ), all the diagonal shifts must have the same cost (denoted as b ), and all knight’s moves must have the same cost (denoted as c ). For the CV_DIST_C and CV_DIST_L1 types, the distance is calculated precisely, whereas for CV_DIST_L2 (Euclidean distance) the distance can be calculated only with a relative error (a 5\times 5 mask gives more accurate results). For a,b , and c , OpenCV uses the values suggested in the original paper:

CV_DIST_C	(3\times 3)	a = 1, b = 1
CV_DIST_L1	(3\times 3)	a = 1, b = 2
CV_DIST_L2	(3\times 3)	a=0.955, b=1.3693
CV_DIST_L2	(5\times 5)	a=1, b=1.4, c=2.1969
Typically, for a fast, coarse distance estimation CV_DIST_L2, a 3\times 3 mask is used. For a more accurate distance estimation CV_DIST_L2 , a 5\times 5 mask or the precise algorithm is used. Note that both the precise and the approximate algorithms are linear on the number of pixels.

The second variant of the function does not only compute the minimum distance for each pixel (x, y) but also identifies the nearest connected component consisting of zero pixels (labelType==DIST_LABEL_CCOMP) or the nearest zero pixel (labelType==DIST_LABEL_PIXEL). Index of the component/pixel is stored in \texttt{labels}(x, y) . When labelType==DIST_LABEL_CCOMP, the function automatically finds connected components of zero pixels in the input image and marks them with distinct labels. When labelType==DIST_LABEL_CCOMP, the function scans through the input image and marks all the zero pixels with distinct labels.

In this mode, the complexity is still linear. That is, the function provides a very fast way to compute the Voronoi diagram for a binary image. Currently, the second variant can use only the approximate distance transform algorithm, i.e. maskSize=CV_DIST_MASK_PRECISE is not supported yet.

Note
An example on using the distance transform can be found at opencv_source_code/samples/cpp/distrans.cpp
(Python) An example on using the distance transform can be found at opencv_source/samples/python2/distrans.py

#### Django 版本不兼容报错 AuthenticationMiddleware

数据库李魔佛 发表了文章 • 0 个评论 • 337 次浏览 • 2019-07-04 15:43 • 来自相关话题

Django 2.2.ERRORS:
?: (admin.E408) 'django.contrib.auth.middleware.AuthenticationMiddleware' must be in MIDDLEWARE in order to use the admin application.
在之前的版本上没有问题，更新后就出错。
降级Django

pip install django=2.1.7

PS: 这个django的版本兼容的确是个大问题，哪天升级了下django版本，不经过严格的测试就带来灾难性的后果。 查看全部
Django 2.2.
ERRORS:
?: (admin.E408) 'django.contrib.auth.middleware.AuthenticationMiddleware' must be in MIDDLEWARE in order to use the admin application.

在之前的版本上没有问题，更新后就出错。
降级Django

pip install django=2.1.7

PS: 这个django的版本兼容的确是个大问题，哪天升级了下django版本，不经过严格的测试就带来灾难性的后果。

#### Win10下PhantomJS无法运行 【版本兼容问题】

python李魔佛 发表了文章 • 0 个评论 • 257 次浏览 • 2019-07-04 09:07 • 来自相关话题

以前在win7上运行的好好的。
在win10下就报错：
selenium.common.exceptions.WebDriverException: Message: Service C:\Tool\phantomjs-2.5.0-beta2-windows\phantomjs-2.5.0-beta2-windows\bin\phantomjs.exe unexpectedly exited. Status code was: 4294967295

后来替换了一个旧的版本，发现问题就这么解决了。
旧版本：phantomjs-2.1.1-windows

原创文章
转载请注明出处
http://30daydo.com/article/505
查看全部
以前在win7上运行的好好的。
在win10下就报错：
selenium.common.exceptions.WebDriverException: Message: Service C:\Tool\phantomjs-2.5.0-beta2-windows\phantomjs-2.5.0-beta2-windows\bin\phantomjs.exe unexpectedly exited. Status code was: 4294967295

后来替换了一个旧的版本，发现问题就这么解决了。
旧版本：phantomjs-2.1.1-windows

原创文章
转载请注明出处
http://30daydo.com/article/505

#### nunpy中的std标准差是样本差吗

量化交易李魔佛 发表了文章 • 0 个评论 • 158 次浏览 • 2019-07-01 10:08 • 来自相关话题

写个代码测试下：
# 测试一下那个方差
x=[1,2,3,4,5,6,7,8,9,10]
X = np.array(x)
X.mean()
5.5

X.std() # 标准差
2.8722813232690143

手工计算一下：
def my_fangca(X):
l=len(X)
mean=X.mean()
sum_ = 0
sum_std=0
for i in X:
sum_+=(i-mean)**2
var_=sum_/l
std_=(sum_/(l))**0.5
return var_,std_
result = my_fangca(X)
得到的result

(8.25, 2.8722813232690143)

说明numpy的std是标准差，不是样本差 查看全部
写个代码测试下：
# 测试一下那个方差
x=[1,2,3,4,5,6,7,8,9,10]
X = np.array(x)

X.mean()
5.5

X.std() # 标准差
2.8722813232690143

手工计算一下：
def my_fangca(X):
l=len(X)
mean=X.mean()
sum_ = 0
sum_std=0
for i in X:
sum_+=(i-mean)**2
var_=sum_/l
std_=(sum_/(l))**0.5
return var_,std_

result = my_fangca(X)
得到的result

(8.25, 2.8722813232690143)

说明numpy的std是标准差，不是样本差

#### 喜马拉雅app 爬取音频文件

python爬虫李魔佛 发表了文章 • 0 个评论 • 847 次浏览 • 2019-06-30 12:24 • 来自相关话题

爬取喜马拉雅app上 杨继东的投资之道 的音频文件
运行环境：python3# -*- coding: utf-8 -*-
# website: http://30daydo.com
# @Time : 2019/6/30 12:03
# @File : main.py

import requests
import re
url = 'https://www.ximalaya.com/revision/play/album?albumId=23057324&pageNum=1&sort=1&pageSize=60'

js_data = r.json()
data_list = js_data.get('data',{}).get('tracksAudioPlay',)
for item in data_list:
trackName=item.get('trackName')
trackName=re.sub(':','',trackName)
src_url = item.get('src')
try:
except Exception as e:
print(e)
print(trackName)
else:
with open('{}.m4a'.format(trackName),'wb') as f:
f.write(r0.content)
保存为main.py
然后运行 python main.py
稍微等几分钟就自动下载好了。

附下载好的音频文件：
提取码：e3zb

原创文章
转载请注明出处
http://30daydo.com/article/503 查看全部
爬取喜马拉雅app上 杨继东的投资之道 的音频文件
运行环境：python3
# -*- coding: utf-8 -*-
# website: http://30daydo.com
# @Time : 2019/6/30 12:03
# @File : main.py

import requests
import re
url = 'https://www.ximalaya.com/revision/play/album?albumId=23057324&pageNum=1&sort=1&pageSize=60'

js_data = r.json()
data_list = js_data.get('data',{}).get('tracksAudioPlay',)
for item in data_list:
trackName=item.get('trackName')
trackName=re.sub(':','',trackName)
src_url = item.get('src')
try:
except Exception as e:
print(e)
print(trackName)
else:
with open('{}.m4a'.format(trackName),'wb') as f:
f.write(r0.content)
print('{} downloaded'.format(trackName))

保存为main.py
然后运行 python main.py
稍微等几分钟就自动下载好了。

附下载好的音频文件：
提取码：e3zb

原创文章
转载请注明出处
http://30daydo.com/article/503

#### python3与python2迭代器的写法的区别

python李魔佛 发表了文章 • 0 个评论 • 153 次浏览 • 2019-06-26 11:22 • 来自相关话题

大部分相同，只是python2里面需要实现在类中实现next()方法，而python3里面需要实现__next__()方法。

附一个例子：
def iter_demo():

class DefineIter(object):

def __init__(self,length):
self.length = length
self.data = range(self.length)
self.index=0

def __iter__(self):
return self

def __next__(self):

if self.index >=self.length:
# return None
raise StopIteration

d = self.data[self.index]*50
self.index =self.index + 1

return d

a = DefineIter(10)
print(type(a))
for i in a:
print(i) 查看全部
大部分相同，只是python2里面需要实现在类中实现next()方法，而python3里面需要实现__next__()方法。

附一个例子：
def iter_demo():

class DefineIter(object):

def __init__(self,length):
self.length = length
self.data = range(self.length)
self.index=0

def __iter__(self):
return self

def __next__(self):

if self.index >=self.length:
# return None
raise StopIteration

d = self.data[self.index]*50
self.index =self.index + 1

return d

a = DefineIter(10)
print(type(a))
for i in a:
print(i)

#### PyCharm 快捷键快速插入当前时间

python李魔佛 发表了文章 • 0 个评论 • 185 次浏览 • 2019-06-26 09:18 • 来自相关话题

个人觉得这是一个非常常用的功能，不过需要自定义实现。

方式
通过 Live Template 快速添加时间

步骤
1、添加一个 Template Group 命名为 Common
2、添加一个 Live Template 设置如下
Abbreviation： time
Description ： current time
Template Text: $time$

Edit Variables -> Expresssion : date("yyyy-MM-dd HH:mm:ss")

3、让设置生效
Define->Everywhere

4、使用
输入 time 后 按下tab键 就能转换为当前时间了
查看全部
个人觉得这是一个非常常用的功能，不过需要自定义实现。

方式
通过 Live Template 快速添加时间

步骤
1、添加一个 Template Group 命名为 Common
2、添加一个 Live Template 设置如下
Abbreviation： time
Description ： current time
Template Text:  $time$

Edit Variables ->  Expresssion : date("yyyy-MM-dd HH:mm:ss")

3、让设置生效
Define->Everywhere

4、使用
输入 time 后 按下tab键 就能转换为当前时间了

#### 深圳转债转股后不可以撤单

股票李魔佛 发表了文章 • 0 个评论 • 149 次浏览 • 2019-06-25 09:12 • 来自相关话题

亲身经历，深圳转债转股后可以撤单操作，并显示已撤单，但是晚上正常转股了。
说明转股后也是不能撤单的。
亲身经历，深圳转债转股后可以撤单操作，并显示已撤单，但是晚上正常转股了。
说明转股后也是不能撤单的。