Today's Question:  What does your personal desk look like?        GIVE A SHOUT

SEARCH KEYWORD -- OUTPUT

   Python – parallelizing CPU-bound tasks with multiprocessing

In a previous post on Python threads, I briefly mentioned that threads are unsuitable for CPU-bound tasks, and multiprocessing should be used instead. Here I want to demonstrate this with benchmark numbers, also showing that creating multiple processes in Python is just as simple as creating multiple threads. First, let’s pick a simple computation to use for the benchmarking. I don’t want it to be completely artificial, so I’ll use a dumbed-down version of factorization...

   Python,Multitasking,Multiprocessing,CPU bound     2012-01-17 11:38:22

  Use rsync to delete mass files quickly in Linux

Yesterday I encountered an issue to delete many log files in my Linux workstation, there were around 100,000 files to be deleted. These are log files and they grow very fast, and we need to delete them frequently. Usually we would use rm -rf * to delete these files, but we may need to wait for a relative long time if there are too many files. So we must adopt some unusual way. Fortunately, we can use rsync to delete mass files in one shot. 1. Install rsync yum install rsync 2. Create a new empty...

   rsync,delete file, demo     2012-11-13 10:44:50

  Canonicalize XML in Java

XML canonicalization is often used when there is need to create digital signature to be sent to peers for verification. Since digital signature is created based on XML data, the XML data has to be canonicalized before its signature value can be calculated. Even an extra space may affect the signature value calculated, hence it must follow some rules to canonicalize the XML data so that it has a standard format. This is why W3C created specification Canonical XML Version 1.1. This specificat...

   JAVA,XML,JAVA SECURITY     2016-01-20 01:39:45

  How to Convert Images on Mac Finder

If you have a lot of images in different formats and you want to convert them to a common format, you can use the Mac Finder to do it easily and quickly. Here are the steps to follow: 1. Open the Finder and navigate to the folder where your images are stored. 2. Select the images that you want to convert. You can use the Shift key or the Command key to select multiple images at once. 3. Right-click on the selected images and choose Services > Preview from the context menu. This will open the ...

   MACOS,FINDER,IMAGE CONVERSION     2023-04-16 02:09:54

  Tips of Drafting an R Markdown Document

When presenting the data summary and exploratory analysis, we used to copy a lot of tables, charts from Rstudio to PowerPoint, which makes the presentation preparation painful. It becomes essential for data scientists to make use of better reporting tools, such as R markdown, Jupyter notebook to prepare the analysis presentation in a more efficient and organized way. Of course, we want this to be reproducible! In this post, I would like to share some tips of using the right tools to draw tables,...

   R PROGRAMMING     2020-11-01 23:09:45

  Tips to improve JavaScript efficiency

Writing JavaScript code is tedious and error prone. You not only need to implement the necessary functions, but also need to ensure cross browser compatibility. This often causes the low efficiency of JavaScript developers. Here we recommend 12 tips you can benefit from. 1. Remove array element by index If we want to remove one element in an array, we can use splice. function removeByIndex(arr, index) { arr.splice(index, 1); } test = new Array(); test[0] = ’Apple’; test[1] = &rsq...

   JavaScript,Tips,Array     2013-07-27 20:50:40

  Understanding JavaScript closure and where it can be used

Closure The official definition of closure is: an expression (usually a function) that has many variables and is bound to an environment that includes those variables. In JavaScript, closure refers to the ability of a function to access the lexical scope in which it was defined, even after the function has been executed and left that scope. This ability is due to the fact that when a function is created, it generates a closure that includes a reference to the definition environment of the curr...

   CLOSURE,JAVASCRIPT,USAGE     2023-03-05 02:17:08

  Memory related exception analysis in Java

Java Virtual Machine Specification divides the memory of JVM into several areas : Heap, Stack, The Program Counter register and Method area etc. In HotSpot JVM, heap is composed of Young, Tenured and Perm. There are different OutOfMemory error can happen in different memory area. Next is an overview of some of these OOM errors. StackOverflowError The JVM will allow only a specified number of stacks created nested. An JVM option -Xss can be set to determine the maximum stack size. If the num...

   Java, Memory model, Memory exception, OOM     2015-01-19 06:54:27

  Algorithm : Reverse singly linked list

Questions about singly linked list are the lovers of interviewers during interviews given the characteristic that singly linked list is one-directional list and it's difficult to get the previous node of one node without some buffering tricks.  In this post, we will demonstrate one of the most frequently asked question about singly linked list -- Reversing the singly list. Given the first node of a singly linked list, reverse the singly linked list. For example : A->B->C->D After ...

   ALGORITHM,INTERVIEW,C     2015-10-31 11:38:35

  Name resolution order in JavaScript

To understand what value a variable has in JavaScript, we need to understand some concepts such as scope and name resolution order. JavaScript has two scopes; one is program level and the other one is function level. Unlike in C,C++ or Java, JavaScript has no block level scope. So a variable defined in a if block will still be available outside. For example, the below example: var foo = 1; function bar() { if (true) { var foo = 10; } alert(foo); } bar(); The alert will display 10 since the ...

   JavaScript,Scope,Name resolution     2013-07-10 01:29:28

RECENT