Zero Proof Knowledge for data set information I understand the Zero Proof Knowledge Protocol concept but find it tricky to implement sometimes for real world cases.

What I would need is, given a file with some key/value (numbers mainly) pairs, the verifier to verify that some values are within a certain range without knowing the information in the file.

Would that be possible with Zero the Proof Knowledge Protocol?

Thanks
Your question actually demonstrates a quite common misconception when it comes to zero knowledge. Unfortunately, you will need some basic complexity background to understand what I'm going to answer. Note: I am not going to talk here about practical and efficiency sides of zero knowledge, but rather the theoretical question of what can be proven.

The famous GMW theorem for zero knowledge is often quoted to say that "anything" can be proven in zero knowledge. However, this is a misconception: rather, it says that any language in $\cal NP$ can be proven in zero knowledge. (I am not going to relate to languages in $IP\setminus NP$ since they do not have efficient provers.) Now, this means that in order to apply zero knowledge, you have to make sure that the statement is in $\cal NP$.

Let's say that a prover $P$ holds a database, and wants to prove to the verifier that certain values are in a range. First, you need to define the $\cal NP$ statement. What would it be here? One option is to say "there exists a database $D$ such that it contains the values in the range...". Well, that's actually a trivial language since for a fixed definition of the values the answer is always yes (and irrespective of any input statement $x$). Basically, the problem here is that there is no statement of reference related to your database, and so this is meaningless.

Therefore, the way to solve this is to have the verifier hold a commitment to the file. This can come in many forms, but consider a public-key encryption scheme with key pairs $(pk,sk)$ and denote the database by $D$. Then, the statement is $c=Enc_{pk}(D)$ and the $\cal NP$-witness is the secret key $sk$. The language is all of the pairs $(pk,c)$ where $c$ is an encryption of $D$ under $pk$ (with the specified public key encryption scheme) and $D$ contains values in the range as defined. Note that $pk$ must be included in the statement since otherwise $c$ doesn't uniquely define $D$.