标签：sys 返回 more end gis col 一个 cee arcpy
UpdateCursor 函数创建一个用于更新或删除指定要素类、shapefile 和表中的行的游标。该游标将数据锁定保留至脚本完成或更新游标对象被删除时。
以迭代方式更新游标的方式有两种：for 循环或者 while 循环（通过游标的 next 方法返回下一行）。如果要使用游标的 next 方法来检索行数为 N 的表中的所有行，脚本必须调用 next N 次。在检索完结果集的最后一行后调用 next 将返回 None，它是一种 Python 数据类型，此处用作占位符。
通过 for 循环使用 UpdateCursor。
import arcpy
fc = "c:/data/base.gdb/roads"
field1 = "field1"
field2 = "field2"
cursor = arcpy.UpdateCursor(fc)
for row in cursor:
# field2 will be equal to field1 multiplied by 3.0
row.setValue(field2, row.getValue(field1) * 3.0)
cursor.updateRow(row)
通过 while 循环使用 UpdateCursor。
import arcpy
fc = "c:/data/base.gdb/roads"
field1 = "field1"
field2 = "field2"
cursor = arcpy.UpdateCursor(fc)
row = cursor.next()
while row:
# field2 will be equal to field1 multiplied by 3.0
row.setValue(field2, row.getValue(field1) * 3.0)
cursor.updateRow(row)
row = cursor.next()
| 参数 | 说明 | 数据类型 |
|
dataset
|
The feature class, shapefile, or table containing the rows to be updated or deleted. |
String |
|
where_clause
|
An optional expression that limits the rows returned in the cursor. For more information on WHERE clauses and SQL statements, see About_building_an_SQL_expression. |
String |
|
spatial_reference
|
Coordinates are specified in the spatial_reference provided and converted on the fly to the coordinate system of the dataset. |
SpatialReference |
|
fields
[fields,...]
|
The fields to be included in the cursor. By default, all fields are included. |
String |
|
sort_fields
|
Fields used to sort the rows in the cursor. Ascending and descending order for each field is denoted by A and D. |
String |
| 数据类型 | 说明 |
| Cursor |
游标对象可分发行对象。 |
根据另一个字段值更新要素类中的字段值。
1 import arcpy 2 3 # Create update cursor for feature class 4 rows = arcpy.UpdateCursor("c:/data/base.gdb/roads") 5 6 # Update the field used in buffer so the distance is based on the 7 # road type. Road type is either 1, 2, 3 or 4. Distance is in meters. 8 for row in rows: 9 # Fields from the table can be dynamically accessed from the 10 # row object. Here fields named BUFFER_DISTANCE and ROAD_TYPE 11 # are used 12 row.setValue("BUFFER_DISTANCE", row.getValue("ROAD_TYPE") * 100) 13 rows.updateRow(row) 14 15 # Delete cursor and row objects to remove locks on the data 16 del row 17 del rows
标签：sys 返回 more end gis col 一个 cee arcpy
原文地址：https://www.cnblogs.com/erickoh/p/14386877.html
