找到数组中最长的匹配字符串

Question

I have an array of hierarchically arranged identifiers (SNMP sysObjectIDs), that I'd like to match against in order to find the closest match.

For example, if my array contains :

.1.3.6.1.4.1.207         = alliedware
.1.3.6.1.4.1.207.1.14    = alliedwareplus
.1.3.6.1.4.1.207.1.4.126 = allied-radlan
.1.3.6.1.4.1.207.1.4.125 = allied-radlan

And I search for

.1.3.6.1.4.1.207.1.14.69

I would like it to return the alliedwareplus entry.

If I search for

.1.3.6.1.4.1.207.1.4

It should return the alliedware entry.

Basically I just want to return the longest match starting from the beginning of the string.

Thanks in advance!

Answer 1

1. Sort the array by the number of components in the object ID, from high to low.
2. Loop through the array, testing whether the object ID in the array is a prefix of the input object ID.
3. When you find a match like this, break out of the loop.

All these steps will probably be easiest if you first convert all the object IDs to an array:

$objid_arr = explode('.', $objid);