undefined offset PHP error
If preg_match did not find a match, $matches is an empty array. So you should check if preg_match found an match before accessing $matches[0], for example:
undefined
PHP Notice: Undefined offset: 1 with array when reading data
Change to or simply: Not every line of your file has a colon in it and therefore explode on it returns an array of size 1. According to php.net possible return values from explode: Returns an array of strings created by splitting the string parameter on boundaries formed by the delimiter. If delimiter is an empty string … Read more
undefined method `each’ for nil:NilClass… why?
In your posts controller, you need to define @posts, which, based on the error you haven’t. As @posts is not defined calling each on it will generate undefined methodeach’ for nil:NilClass`.
C++ identifier is undefined
Reducing to three lines (the other errors are analogous): While wall is defined, gallons is not. And where do you want to get gallons from anyway? The result is hidden deep inside another function. How do you want to get it out from there? Well, you need a return value: This way, you can use your function like this: Analogously for … Read more
How can I determine if a variable is ‘undefined’ or ‘null’?
You can use the qualities of the abstract equality operator to do this: Because null == undefined is true, the above code will catch both null and undefined.
undefined method `each’ for nil:NilClass… why?
In your posts controller, you need to define @posts, which, based on the error you haven’t. As @posts is not defined calling each on it will generate undefined methodeach’ for nil:NilClass`.
Java Undefined Object
By “undefined object as a parameter”, I assume you mean that you’re looking to write a function that doesn’t specify the type of the object in the function declaration, allowing you to only have one function. This can be done with generics. Instead of: you can have: Test: See Java generics for more information.
How to resolve TypeError: Cannot convert undefined or null to object
Generic answer This error is caused when you call a function that expects an Object as its argument, but pass undefined or null instead, like for example As that is usually by mistake, the solution is to check your code and fix the null/undefined condition so that the function either gets a proper Object, or does not get called at all. Answer specific to … Read more
JavaScript null check
An “undefined variable” is different from the value undefined. An undefined variable: A variable with the value undefined: When a function takes an argument, that argument is always declared even if its value is undefined, and so there won’t be any error. You are right about != null followed by !== undefined being useless, though.
JavaScript null check
An “undefined variable” is different from the value undefined. An undefined variable: A variable with the value undefined: When a function takes an argument, that argument is always declared even if its value is undefined, and so there won’t be any error. You are right about != null followed by !== undefined being useless, though.