Using Not Equal in ArcPy SetNull

Question

I am trying to set all values in my raster that are not equal to -9999 to Null using Arcpy. The problem is that using != operator gets me an arcgisscripting.ExecuteError: ERROR 010416: Error in setting raster table filter for F:\Data\test.tif. However, other operators like = or < works okay. Any ideas?

UPDATE

I solved the problem using <> instead of !=, but I still do not understand why ArcGIS and Arcpy use different operators for the same functions.

# Import arcpy module
import arcpy

# Set the current workspace
arcpy.env.workspace = "F:/Data"

# check out any necessary licenses
arcpy.CheckOutExtension("Spatial")

inRaster = arcpy.Raster('test.tif')
outSetNull = arcpy.sa.SetNull(inRaster, in_false_raster_or_constant=1, where_clause='Value != -9999')

Answer 1

!= is Python syntax for does not equal. <> is sql syntax for the same. Since the expression in question is an sql where clause, you must use the sql syntax, even though it’s within a python script.

< and = perform the same function in sql and python (edit: python uses == for equals), which is why python syntax seems to ‘work’ in your sql where clause.