Python - How to get the minimum value that is not zero in each year field in a shapefile table? - shapefile

Question

I am having a problem when trying to extract the minimum value that is not zero of each year in my shapefile table with Python. My table has "Station ID", "Longitude", "Latitude", and year fields with F as the first letter. For example: F1970, F1971,F1972...I intend to loop through each year field,and then sort all the values in each year from smallest to largest, then get the first record not equal to zero, because I only want the value larger than zero. So far, I can only get the first record, which is zero. Could anyone tell me how to modify the code and get the first minimum value that is not zero?Thank you so much!![I want to get the station ID, longitude and latitude that corresponds with the minimum value of each year]
# Obtain the list of all fields in the attribute table of the shapefile "Station"
fields=arcpy.ListFields(Station)
# Construct a for loop to iterate through all the year attribute in the input feature class,in order to find the record with the minimum value in each year.
for field in fields:
year=str(field.name)
# find the year field
if ("F" in year):
where=year+" ASCENDING"
# Process: Sort
arcpy.Sort_management(Station, outputFC, where, "UR")
rows = arcpy.SearchCursor(outputFC)
row=rows.next
for row in rows:
# only got me the first record in each year, which is zero.
value=row.getValue(year)
stationID= row.getValue("Station_ID")
obsLon= row.getValue("Longitude")
obsLat=row.getValue("Latitude")
row=rows.next()
break
del row,rows

Answer 1

You can use the SearchCursor to both filter the rows and sort them.
# Obtain the list of all fields in the attribute table of the shapefile "Station"
fields=arcpy.ListFields(Station)
# Construct a for loop to iterate through all the year attribute in the input feature class,in order to find the record with the minimum value in each year.
for field in fields:
# find the year field
if ("F" in field.name):
year=str(field.name)
where_clause = year + " > 0"
sort_clause = year + " ASCENDING"
# Use a SearchCursor to filter and sort the rows
# Docs: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/SearchCursor/000v00000039000000/
rows = arcpy.SearchCursor(Station, where_clause, "", "", "", sort_clause)
# only got the first record in each year, which is > zero.
row = rows.next()
value=row.getValue(year)
stationID= row.getValue("Station_ID")
obsLon= row.getValue("Longitude")
obsLat=row.getValue("Latitude")
print "Record:", year, value, stationID, obsLon, obsLat
del row,rows