I’ll requote myself from the duplicate post…
[quote=“JordanCClark”]Since you’re looking for only changed values, you would need to grab the previous values. You can do this by either:
1: reading all your tags and comparing the values.
2: renaming the file with the current values to hold the previous values. Then read two files (one with the current values and the one you renamed) and compare.
[/quote]
How many tags are you processing? Depending on the number, there may not be a whole lot of overhead to worry about anyway.