I think the bulletproof way is: if (typeof $.cookie(‘token’) === ‘undefined’){ //no cookie } else { //have cookie } Checking the type of a null, empty or undefined var always returns ‘undefined’ Edit: You can get there even easier: if (!!$.cookie(‘token’)) { // have cookie } else { // no cookie } !! will turn … Read more
To avoid converting to str and actually use the lists, you can do this: df[df[‘donation_orgs’].map(lambda d: len(d)) > 0] It maps the donation_orgs column to the length of the lists of each row and keeps only the ones that have at least one element, filtering out empty lists. It returns Out[1]: donation_context donation_orgs 1 [In … Read more
In standard SQL you can specify where to put nulls: order by col asc nulls first order by col asc nulls last order by col desc nulls first order by col desc nulls last but T-SQL doesn’t comply with the standard here. The order of NULLs depends on whether you sort ascending or descending in … Read more
You have to use CASE SELECT CASE WHEN Field IS NOT NULL THEN ‘something’ ELSE ‘something else’ END
Since aa is the set/object that might be null, can you check aa == null ? (aa / xx might be interchangeable (a typo in the question); the original question talks about xx but only defines aa) i.e. select new { AssetID = x.AssetID, Status = aa == null ? (bool?)null : aa.Online; // a … Read more
In MySQL, NULL is considered as a ‘missing, unknown value’, as opposed to no value. Take a look at this MySQL Reference on NULL. Any arithmetic comparison with NULL does not return true or false, but returns NULL instead., So, NULL != ‘C’ returns NULL, as opposed to returning true. Any arithmetic comparison with ‘NULL’ … Read more
You should check for !test, here is a fiddle showing that. <span ng-if=”!test”>null</span>
This problem reported on Microsoft Connect reveals some differences between COALESCE and ISNULL: an early part of our processing rewrites COALESCE( expression1, expression2 ) as CASE WHEN expression1 IS NOT NULL THEN expression1 ELSE expression2 END. In [this example]: COALESCE ( ( SELECT Nullable FROM Demo WHERE SomeCol = 1 ), 1 ) we generate: … Read more
It’s called the null coalescing (??) operator: myNewValue = myValue ?? new MyValue();
There is absolutely no difference in functionality between is_null and === null. The only difference is that is_null is a function and thus is marginally slower (function call overhead) can be used as a callback, e.g. array_map(‘is_null’, $array). Personally, I use null === whenever I can, as it is more consistent with false === and … Read more