dart:developer library includes inspect function that allows debuggers to open an inspector on the object. To use it add: import ‘dart:developer’; And then you can see your inspected variable/object in console with: inspect(myVar);
You should use null. In most cases it doesn’t matter, but it is a good habit to get into anyway, because occasionally you may want to check if a list of non-comparable things is empty. Here is a short, crisp example showing this difference: > null [id] False > [id] == [] <interactive>:1:1: error: • … Read more
I solved a similar problem using NULLIF function: UPDATE table SET col1 = NULLIF(col1, ”) From the T-SQL reference: NULLIF returns the first expression if the two expressions are not equal. If the expressions are equal, NULLIF returns a null value of the type of the first expression.
For a succinct modern cross-browser implementation, just do: function isNullOrWhitespace( input ) { return !input || !input.trim(); } Here’s the jsFiddle. Notes below. The currently accepted answer can be simplified to: function isNullOrWhitespace( input ) { return (typeof input === ‘undefined’ || input == null) || input.replace(/\s/g, ”).length < 1; } And leveraging falsiness, even … Read more
You should absolutely use isEmpty(). Computing the size() of an arbitrary list could be expensive. Even validating whether it has any elements can be expensive, of course, but there’s no optimization for size() which can’t also make isEmpty() faster, whereas the reverse is not the case. For example, suppose you had a linked list structure … Read more
As long as your selector is actually working, I see nothing wrong with your code that checks the length of the array. That should do what you want. There are a lot of ways to clean up your code to be simpler and more readable. Here’s a cleaned up version with notes about what I … Read more
Using not a to test whether a is None assumes that the other possible values of a have a truth value of True. However, most NumPy arrays don’t have a truth value at all, and not cannot be applied to them. If you want to test whether an object is None, the most general, reliable … Read more
If you’re dealing with optional Strings, this works: (string ?? “”).isEmpty The ?? nil coalescing operator returns the left side if it’s non-nil, otherwise it returns the right side. You can also use it like this to return a default value: (string ?? “”).isEmpty ? “Default” : string!
You can use the :placeholder-shown pseudo class. Technically a placeholder is required, but you can use a space instead. input:not(:placeholder-shown) { border-color: green; } input:placeholder-shown { border-color: red; } <input placeholder=”Text is required” /> <input placeholder=” ” value=”This one is valid” /> <input placeholder=” ” />
Misspellings are irritating, aren’t they? Check your spelling of empty, but then also try this: #!/bin/bash -e if [ -s diff.txt ]; then # The file is not-empty. rm -f empty.txt touch full.txt else # The file is empty. rm -f full.txt touch empty.txt fi I like shell scripting a lot, but one disadvantage of … Read more