Search Within An Array With A Condition

I have two array I'm trying to compare at many levels. Both have the same structure with 3 "columns.The first column contains the polygon's ID, the second a area type, and the third, the percentage of each area type for a polygone.So, for many rows, it will compare, for example, ID : 1 Type : aaa % : 100..But for some elements, I have many rows for the same ID. For example, I'll have ID 2, Type aaa, 25% --- ID 2, type bbb, 25% --- ID 2, type ccc, 50%. And in the second array, I'll have ID 2, Type aaa, 25% --- ID 2, type bbb, 10% --- ID 2, type eee, 38% --- ID 2, type fff, 27%.So, my function has to compare these two array and send me an email if there are differences.(I wont show you the real code because there are 811 lines). The first "if" condition is [code]I have two different layers in a geospatial database. Both layers have the same structure. They are a "spatial join" of the land parcels (55 000), and the land use layer. The first layer is the current one, and the second layer is the next one we'll use after 2015.So I have, for each "land parcel" the percentage of each land use. So, for a "land parcel" (ID 7580-80-2532, I can have 50% of farming use (TYPE FAR-23), and 50% of residantial use (RES-112). In the first array, I'll have 2 rows with the same ID (7580-80-2532), but each one will have a different type (FAR-23, RES-112) and a different %.

In the second layer, the same the municipal zoning (land use) has changed. So the same "land parcel" will now be 40% of residential use (RES-112), 20% of commercial (COM-54) and 40% of a new farming use (FAR-33).So, I wanna know if there are some differences. Some land parcels will be exactly the same. Some parcels will keep the same land use, but not the same percentage of each. But for some land parcel, there will be more or less land use types with different percentage of each.I want this script to compare these two layers and send me an email when there are differences between these two layers for the same land parcel ID.The script is already working, but it takes too much time. The probleme is, I think, the script go through all array2 for each row in array 1. What I want is when there are more than 1 rows with the same ID in array1, take only this ID in both arrays.Maybe if I order them by IDs, I could write a condition. kind of "when you find what you're looking for, stop searching when you'll find a different value?