I am trying to test if each feature of a feature class list intersect each feature of a shapefile (clip layer). I'm working with arcpy in ArcGIS 10.0

The arcgis desktop help says that if the feature comes from a geodatabase, all the features will be copied but if it's a layer, only selected will be copied (http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001700000035000000).

In my code, I'm working with a feature class list from a geodatabase.In order to copy only selected, I first convert each feature class to a feature layer :

for fc in fcList:
    for row in rows:
        where_clause = "secteur = '{0}'".format(secteur)
        arcpy.MakeFeatureLayer_management(pochoir, "ptmp", where_clause)#pochoir is #the clip feature. For each row I make a tmp corresponding to the geometry that I'll use #after.
        arcpy.MakeFeatureLayer_management(fc, "toselect")
        arcpy.SelectLayerByLocation_management("toselect", "INTERSECT", "ptmp")
        arcpy.CopyFeatures_management("toselect", "selected") ## Here is the problem : #"selected" should be empty when not intersecting with "ptmp" but the whole "toselect" (so #the whole fc) is copied even if not intersecting. 
        nbrow = arcpy.GetCount_management("selected")
        outName = "{0}_{1}_{2}".format(fc, secteur, count)

        if nbrow > 0: ## So all the layers goes in the if even if they do not intersect.
            do something
            do something else

What you first want to do is check for a selection. This can be done by checking if arcpy.Describe (layer).FIDSet returns anything. FIDSet is a property of a layer describe object. It returns OIDs of selected features, and nothing if there are no selected features.

Try this after you make your selection:

if arcpy.Describe ("toselect").FIDSet:
    arcpy.CopyFeatures_management("toselect", "selected")

If you want an empty feature class returned when there is no selection, you'll have to code an else: make feature class, or something along those lines.

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