There are many kinds of blank or empty values, that mean different things.
Table of Contents
Zero
Zero means quantitatively or numerically none, implying that a numeric value exists.
What does that mean?
What is a Value?
“Value” is a quantitative or qualitative aspect or attribute.
As an example, something could have monetary value (cost), quantitative value (representation of a number), or qualitative value (such as “blue” or “good”).
If we say something has the value of “zero”, we are implying that it represents or is equivalent to the quantity zero, but that it DOES have a numeric quality (quantitative value).
Blank
Blank is an empty value.
When we say something is “blank”, we mean that there is nothing there. What we really mean is a space where SOMETHING could be stored or written.
Blank means that the specified value exists but is empty.
As an example, when you adopt a puppy, we know that puppies have names, but perhaps you haven’t given it a name yet. The space exists for the puppy’s name, but the name is currently blank.
Blank is represented by an empty string: “”
Empty
Empty is a set with nothing in it.
A set is a group of similar things, such as letters, numbers, weather temperatures, or airplane velocities.
A set with nothing in it has no members, and is therefore “empty”
In math, an empty set looks like this: { }
Null
Null means that a value exists, but the blank for it hasn’t been created yet.
For example, some people name their cars, and others don’t. Every car could have a name, but perhaps this particular car doesn’t have one. This car’s name is a null value.
In programming, a pointer is initially not pointing to anything, and is said to be “Null”.
A null value is represented by: -0-
Nothing
“Nothing” is the opposite of “something”.
If you have no car, your car is equal to nothing. If you have no puppy, your puppy is equal to nothing.
In programming, “nothing” is used to de-reference a pointer, and release the memory used by the memory structure it had been using.
On a side note, if you have no car, and no puppy, you must be really sad!
Undefined
Beyond “nothing”, which is the lack of “something”, undefined means that the “something” in question can never exist.
For example, the square root of -1 can’t exist — any number multiplied by itself yields a positive integer. In math, this is resolved using the “imaginary” number, i.
Another example is dividing some number by zero. Division means taking a quantity of somethings (the dividend) and putting them evenly in the number of specified buckets (the divisor) to determine how many somethings go in each bucket (the quotient). As the divisor decreases (fewer buckets), the quotient gets larger. Fractional buckets yield quotients that are much larger than the original quantity of somethings. If you put 8 somethings in 4 buckets, 2 is the quotient. If you put the same 8 somethings in 1/2 bucket, the answer is 16! As the size of the bucket approaches zero, the resulting answer approaches infinity!
From a procedural standpoint, putting x amount of somethings in to 0 buckets makes no sense.