Question

尝试使用Python在shapefile表中提取每年不为零的最小值时遇到问题。我的桌子有“Station ID”，“Longitude”，“Latitude”和年份字段，以F为首字母。例如：F1970，F1971，F1972 ......我打算遍历每年的字段，然后将每年的所有值从最小值排序到最大值，然后得到第一个不等于零的记录，因为我只想要值大于零。到目前为止，我只能获得第一条记录，即零。谁能告诉我如何修改代码并获得第一个不为零的最小值？非常感谢!! [我希望获得与每年最小值相对应的车站ID，经度和纬度]

 # 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

您可以使用SearchCursor过滤行并对其进行排序。

# 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

Python - 如何在shapefile表中获取每年字段中不为零的最小值？

1 个答案: