I have a project in which I need to convert a byte into an integer: <?php $a=md5(“hello”,true); echo $a[15]*1.0/255.0; The second parameter of md5 is set to true in order […]

In python, you have many ways to represent a 2-dimensional array. You can use list like:[[1,2],[3,4],[5,6]], you can use ndarray in numpy like:numpy.array([[1,2],[3,4],[5,6]]), you can also use dataframe in the […]

If you learn python based AI software such as tensorflow, you’ll inevitably meet the package Numpy and DataFrame,etc. So you must learn how to use Numpy and DataFrame before you […]

In Qt, there seem a lot of classes related to XML:QDomDocument, QXmlStreamReader,QXmlSimpleReader,etc. You can choose any one to parse an XML document.  QDomDocument is more powerful but keep all content […]

Creating dll seems an easy task in Qt. In Qt creator,  click File/New File or Project/Projects/Library/C++ Library, then simply choose a name, you will create a dll project. Click “build”, […]

I use some RSA encrypt/decrypt functions in openssl lib so I installed the latest openssl lib 1.1.0 and imported the lib into my Qt project. I thought  my Qt was […]

Although you can use QSettings to access Windows registry, sometimes it is more convenient to use Windows API directly,i.e., you are porting an old project that uses Windows API. The […]

The constructor of QWidget has an optional parameter:parent. I did not take care about this parameter in the past. Sometimes I create a QWidget  object without providing the parent parameter, […]