idioms or patterns in students learning to program

I'm looking for some information about recurring patterns or forms of coding. I found that patterns and idioms have similar definitions, and the only thing that differentiates them is perhaps the size of the code that is repeated. Now, I am analyzing several pseudo-codes from first-time programming students, and I want to determine some things with this information, for example, that they first declare variables or directly go on to solve the problem, or perhaps determine if they use some Loop Structures , among other things. What I want to ask is: the term idiom is big enough to say that, for example, that most first-time students prefer to use the while lopp instead of the for, so it is a first-time student programming idiom. Or is there a more accurate term?,

Sorry if it is not very understandable, but I am not a native English speaker,