No error , No gain

What is this? This is a collection of questions that come up every now and then about syntax in PHP. This is also a Community Wiki, so everyone is invited to participate in maintaining this list. Why is this? It used to be hard to find questions about operators and other syntax tokens.¹ The main idea is to have links to existing questions on Stack Overflow, so it's easier for us to reference the..

Also how do LEFT JOIN, RIGHT JOIN and FULL JOIN fit in? Assuming you're joining on columns with no duplicates, which is a very common case: An inner join of A and B gives the result of A intersect B, i.e. the inner part of a Venn diagram intersection. An outer join of A and B gives the results of A union B, i.e. the outer parts of a Venn diagram union. Examples Suppose you have two tables, with ..

I forked a project, applied several fixes and created a pull request which was accepted. A few days later, another change was made by another contributor. So my fork doesn't contain that change. How can I get that change into my fork? Do I need to delete and re-create my fork when I have further changes to contribute? Or is there an update button? In your local clone of your forked repository, y..

How do you delete a Git tag that has already been pushed? You can push an 'empty' reference to the remote tag name: git push origin :tagname Or, more expressively, use the --delete option (or -d if your git version is older than 1.8.0): git push --delete origin tagname Note that git has tag namespace and branch namespace so you may use the same name for a branch and for a tag. If you want to mak..

How do I make the first letter of a string uppercase, but not change the case of any of the other letters? For example: "this is a test" → "This is a test" "the Eiffel Tower" → "The Eiffel Tower" "/index.html" → "/index.html" The basic solution is: function capitalizeFirstLetter(string) { return string.charAt(0).toUpperCase() + string.slice(1); } console.log(capitalizeFirstLetter('foo')); // Foo..

What command can be used to check if a directory exists or not, within a Bash shell script? To check if a directory exists in a shell script, you can use the following: if [ -d "$DIRECTORY" ]; then # Control will enter here if $DIRECTORY exists. fi Or to check if a directory doesn't exist: if [ ! -d "$DIRECTORY" ]; then # Control will enter here if $DIRECTORY doesn't exist. fi However, as Jon Er..

I'd like to do something like this to tick a checkbox using jQuery: $(".myCheckBox").checked(true); or $(".myCheckBox").selected(true); Does such a thing exist? Modern jQuery Use .prop(): $('.myCheckbox').prop('checked', true); $('.myCheckbox').prop('checked', false); DOM API If you're working with just one element, you can always just access the underlying HTMLInputElement and modify its .check..

What are the differences between a HashMap and a Hashtable in Java? Which is more efficient for non-threaded applications? There are several differences between HashMap and Hashtable in Java: Hashtable is synchronized, whereas HashMap is not. This makes HashMap better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones. Hashtable does not allo..

Something similar to Unix's timestamp, that is a single number that represents the current time and date. Either as a number or a string. Short & Snazzy: + new Date() A unary operator like plus triggers the valueOf method in the Date object and it returns the timestamp (without any alteration). Details: On almost all current browsers you can use Date.now() to get the UTC timestamp in millisecond..

I keep rereading the Docker documentation to try to understand the difference between Docker and a full VM. How does it manage to provide a full filesystem, isolated networking environment, etc. without being as heavy? Why is deploying software to a Docker image (if that's the right term) easier than simply deploying to a consistent production environment? Docker originally used LinuX Containers..