删除字段

摘要

此工具可从表、要素类、要素图层或栅格数据集中删除一个或多个字段。

用法

• 此工具适用于任何表；ArcSDE、文件或个人地理数据库要素类；coverage；栅格数据集或 shapefile。

• 不能从 ArcGIS 的非本地只读数据格式中删除字段，例如：VPF 和 CAD 数据集。

• 删除字段参数的添加字段按钮仅可以在“模型构建器”中使用。在模型构建器中，如果先前的工具尚未运行或其派生数据不存在，则可能不会使用字段名称来填充删除字段参数。添加字段按钮可用于添加所需字段，以完成“删除字段”对话框并继续构建模型。

语法

DeleteField_management (in_table, drop_field)

参数	说明	数据类型
in_table	包含要删除字段的表。将修改现有输入表。	Mosaic Layer; Raster Catalog Layer; Raster Layer; Table View
drop_field [drop_field,...]	要从输入表中删除的字段。必填字段不能删除。	Field

代码实例

DeleteField 示例（Python 窗口）

以下 Python 窗口脚本演示了如何在即时模式下使用 DeleteField 工具：

import arcpy
arcpy.env.workspace = "C:/data"
arcpy.CopyFeatures_management("majorrds.shp", "C:/output/majorrds_copy.shp")
arcpy.DeleteField_management("C:/output/majorrds_copy.shp", 
                             ["STREET_NAM", "LABEL", "CLASS"])

DeleteField 示例 2（独立脚本）

以下独立脚本演示了如何使用 DeleteField 工具：

# Name: DeleteField_Example2.py
# Description: Delete several fields from a feature class
  
# Import system modules
import arcpy
 
# Set environment settings
arcpy.env.workspace = "C:/data"
 
# Set local variables
inFeatures = "accident.dbf"
outFeatureClass = "C:/output/new_accident.dbf"
dropFields = ["STREET_NAM", "LABEL", "CLASS"]
 
# Execute CopyFeatures to make a new copy of the feature class
#  Use CopyRows if you have a table
arcpy.CopyFeatures_management(inFeatures, outFeatureClass)
 
# Execute DeleteField
arcpy.DeleteField_management(outFeatureClass, dropFields)

DeleteField 示例 3（独立脚本）

使用 DeleteField 可从要素类或表中清除所有不需要的字段。

# Name: DeleteFields_clearfields.py
# Description: Delete unrequired fields from a feature class or tble.
 
# Import system modules
import arcpy
 
try: 
    # Get user-supplied input and output arguments
    inTable = arcpy.GetParameterAsText(0)
    updatedTable = arcpy.GetParameterAsText(1)
 
    # Describe the input (need to test the dataset and data types)
    desc = arcpy.Describe(updatedTable)
 
    # Make a copy of the input (so we can mantain the original as is)
    if desc.datasetType == "FeatureClass":
        arcpy.CopyFeatures_management(inTable, updatedTable)
    else:
        arcpy.CopyRows_management(inTable, updatedTable)
 
    # Use ListFields to get a list of field objects
    fieldObjList = arcpy.ListFields(updatedTable)
 
    # Create an empty list that will be populated with field names        
    fieldNameList = []
 
    # For each field in the object list, add the field name to the
    #  name list.  If the field is required, exclude it, to prevent errors
    for field in fieldObjList:
        if not field.required:
            fieldNameList.append(field.name)
 
    # dBASE tables require a field other than an OID and Shape.  If this is
    #  the case, retain an extra field (the first one in the original list)
    if desc.dataType in ["ShapeFile", "DbaseTable"]:
        fieldNameList = fieldNameList[1:]
 
    # Execute DeleteField to delete all fields in the field list. 
    arcpy.DeleteField_management(updatedTable, fieldNameList)
          
except Exception as err:
    print(err.args[0])

环境

• 当前工作空间

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