What is the role of the package-lock.json?

It stores an exact, versioned dependency tree rather than using starred versioning like package.json itself (e.g. 1.0.*). This means you can guarantee the dependencies for other developers or prod releases, etc. It also has a mechanism to lock the tree but generally will regenerate if package.json changes. From the npm docs: package-lock.json is automatically generated for any operations where npm … Read more

Categories npm

How to use mysqli_query() in PHP?

I have to admit, mysqli_query() manual entry doesn’t contain a clean example on how to fetch multiple rows. May be it’s because the routine is so routine, known to PHP folks for decades: In case you want to print the column titles, you have to select your data into a nested array first and then use keys … Read more

Can comments be used in JSON?

No. The JSON is data only, and if you include a comment, then it will be data too. You could have a designated data element called “_comment” (or something) that should be ignored by apps that use the JSON data. You would probably be better having the comment in the processes that generates/receives the JSON, as they … Read more

How to list containers in Docker

To show only running containers use the given command: To show all containers use the given command: To show the latest created container (includes all states) use the given command: To show n last created containers (includes all states) use the given command: To display total file sizes use the given command: The content presented above is from docker.com. In the new version of Docker, commands … Read more

C-like structures in Python

Use a named tuple, which was added to the collections module in the standard library in Python 2.6. It’s also possible to use Raymond Hettinger’s named tuple recipe if you need to support Python 2.4. It’s nice for your basic example, but also covers a bunch of edge cases you might run into later as well. Your fragment above would … Read more

Understanding Python super() with __init__() methods [duplicate]

super() lets you avoid referring to the base class explicitly, which can be nice. But the main advantage comes with multiple inheritance, where all sorts of fun stuff can happen. See the standard docs on super if you haven’t already. Note that the syntax changed in Python 3.0: you can just say super().__init__() instead of super(ChildB, self).__init__() which IMO is quite a bit nicer. The … Read more

What is the best way to use a HashMap in C++?

The standard library includes the ordered and the unordered map (std::map and std::unordered_map) containers. In an ordered map the elements are sorted by the key, insert and access is in O(log n). Usually the standard library internally uses red black trees for ordered maps. But this is just an implementation detail. In an unordered map insert and access is in … Read more