I am reading first line of all the files in a directory, on local it works fine but on EMR this test is failing at stuck at around 200-300th file. Also ps -eLF show increase of childs to 3000 even print in on 200th line. It this some bug on EMR to read max bytes? pydoop version pydoop==0.12.0 import os import sys import shutil import codecs import pydoop.hdfs as hdfs def prepare_data(hdfs_
我正在阅读目录中所有文件的第一行，在本地它可以正常工作，但在EMR上，此测试未能停留在第200-300个文件。 另外ps -eLF显示，在200号线上甚至可以打印3000张儿童。 这是EMR读取最大字节数的一些错误？ pydoop版本pydoop == 0.12.0 import os import sys import shutil import codecs import pydoop.hdfs as hdfs def prepare_data(hdfs_folder): folder = "test_folder" copies_count = 700 src_file = "file
I know I should avoid using global variables in the first place due to confusion like this, but if I were to use them, is the following a valid way to go about using them? (I am trying to call the global copy of a variable created in a separate function.) x = somevalue def func_A (): global x # Do things to x return x def func_B(): x=func_A() # Do things return x func_A() f
我知道我应该首先避免使用全局变量，因为这样会造成混淆，但是如果我使用它们，下面是使用它们的有效方法吗？ （我试图调用一个独立函数中创建的变量的全局副本。） x = somevalue def func_A (): global x # Do things to x return x def func_B(): x=func_A() # Do things return x func_A() func_B() 第二个函数使用的x是否具有与func_a使用和修改的x的全局副本相同的值？ 定义后调用函数时，命令是
i'm having a very tough time searching google image search with python. I need to do it using only standard python libraries (so urllib, urllib2, json, ..) Can somebody please help? Assume the image is jpeg.jpg and is in same folder I'm running python from. I've tried a hundred different code versions, using headers, user-agent, base64 encoding, different urls (images.google.com
我有一个非常艰难的时间搜索谷歌图像搜索与Python。 我只需要使用标准的Python库（so urllib，urllib2，json，...） 有人可以帮忙吗？ 假设图像是jpeg.jpg，并在我运行python的同一个文件夹中。 我已经尝试了数百种不同的代码版本，使用标题，用户代理，base64编码，不同的URL（images.google.com，http://images.google.com/searchbyimage?hl=zh-CN&biw=1060&bih=766&gbv=2&site = search＆image_url = {
I'm following the official documentation, trying to read a video from a webcam. As I run the piece of code from the documentation: import numpy as np import cv2 cap = cv2.VideoCapture(0) while(True): # Capture frame-by-frame ret, frame = cap.read() # Our operations on the frame come here gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # Display the resulting frame
我遵循官方文档，试图从网络摄像头读取视频。 当我从文档中运行一段代码时： import numpy as np import cv2 cap = cv2.VideoCapture(0) while(True): # Capture frame-by-frame ret, frame = cap.read() # Our operations on the frame come here gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # Display the resulting frame cv2.imshow('frame',gray) if cv2.waitKey(1) & 0xFF == o
How do you capture video from two or more cameras at once (or nearly) with OpenCV, using the Python API? I have three webcams, all capable of video streaming, located at /dev/video0, /dev/video1, and /dev/video2. Using the tutorial as an example, capturing images from a single camera is simply: import cv2 cap0 = cv2.VideoCapture(0) ret0, frame0 = cap0.read() cv2.imshow('frame', frame0) cv2.w
如何使用Python API同时（或几乎）使用OpenCV从两台或更多台摄像机捕获视频？ 我有三个网络摄像头，都可以进行视频流传输，位于/ dev / video0，/ dev / video1和/ dev / video2。 以该教程为例，从单个相机捕捉图像很简单： import cv2 cap0 = cv2.VideoCapture(0) ret0, frame0 = cap0.read() cv2.imshow('frame', frame0) cv2.waitKey() 这工作正常。 但是，如果我尝试初始化第二个摄像头，试图从它read()返回None
I am trying to understand exceptions with Python 2.7.6, on Windows 8. Here's the code I am testing, which aims to create a new directory at My_New_Dir . If the directory already exists, I want to delete the entire directory and its contents, and then create a fresh directory. import os dir = 'My_New_Dir' try: os.mkdir(dir) except IOError as e: print 'exception thrown' shutil.
我想在Windows 8上理解Python 2.7.6的异常。 这是我正在测试的代码，其目的是在My_New_Dir上创建一个新目录。 如果该目录已经存在，我想删除整个目录及其内容，然后创建一个新的目录。 import os dir = 'My_New_Dir' try: os.mkdir(dir) except IOError as e: print 'exception thrown' shutil.rmtree(dir) os.mkdir(dir) 事情是，这个例外永远不会抛出。 如果该目录尚不存在，代码工作正常，但如果目录
I use Python 3.4 from the Anaconda distribution. Within this distribution, I found the pymysql library to connect to an existing MySQL database, which is located on another computer. import pymysql config = { 'user': 'my_user', 'passwd': 'my_passwd', 'host': 'my_host', 'port': my_port } try: cnx = pymysql.connect(**config) except pymysql.err.Operatio
我使用Anaconda发行版中的Python 3.4。 在这个发行版中，我发现pymysql库连接到位于另一台计算机上的现有MySQL数据库。 import pymysql config = { 'user': 'my_user', 'passwd': 'my_passwd', 'host': 'my_host', 'port': my_port } try: cnx = pymysql.connect(**config) except pymysql.err.OperationalError : sys.exit("Invalid Input: Wrong username/database or
According to http://docs.sqlalchemy.org/en/rel_0_9/core/pooling.html#disconnect-handling-pessimistic, SQLAlchemy can be instrumented to reconnect if an entry in the connection pool is no longer valid. I create the following test case to test this: import subprocess from sqlalchemy import create_engine, event from sqlalchemy import exc from sqlalchemy.pool import Pool @event.listens_for(Pool, "
根据http://docs.sqlalchemy.org/en/rel_0_9/core/pooling.html#disconnect-handling-pessimistic，如果连接池中的条目不再有效，可以检测SQLAlchemy重新连接。 我创建了以下测试用例来测试它： import subprocess from sqlalchemy import create_engine, event from sqlalchemy import exc from sqlalchemy.pool import Pool @event.listens_for(Pool, "checkout") def ping_connection(dbapi_connection, connection_record,
I am trying to implement the closest pair problem in Python using divide and conquer, everything seems to work fine except that in some input cases, there is a wrong answer. My code is as follows: def closestSplitPair(Px,Py,d): X = Px[len(Px)-1][0] Sy = [item for item in Py if item[0]>=X-d and item[0]<=X+d] best,p3,q3 = d,None,None for i in xrange(0,len(Sy)-2): for
我试图在Python中使用分而治之来实现最接近的对问题，除了在某些输入情况下，一切都似乎正常工作，但有错误的答案。 我的代码如下： def closestSplitPair(Px,Py,d): X = Px[len(Px)-1][0] Sy = [item for item in Py if item[0]>=X-d and item[0]<=X+d] best,p3,q3 = d,None,None for i in xrange(0,len(Sy)-2): for j in xrange(1,min(7,len(Sy)-1-i)): if dist(Sy[i],Sy[i+j]) &l
How can I describe a grammar using regex (or pyparsing is better?) for a script languge presented below (Backus–Naur Form): <root> := <tree> | <leaves> <tree> := <group> [* <group>] <group> := "{" <leaves> "}" | <leaf>; <leaves> := {<leaf>;} leaf <leaf> := <name> = <expression>{;} <
我如何使用正则表达式来描述语法（或者pyparsing更好？），以下是一个脚本语言（Backus-Naur Form）： <root> := <tree> | <leaves> <tree> := <group> [* <group>] <group> := "{" <leaves> "}" | <leaf>; <leaves> := {<leaf>;} leaf <leaf> := <name> = <expression>{;} <name> := <st