Python for ArcGIS：向形状文件添加文本字段，然后搜索一个字段，如果满足条件，则更新另一个字段答案

【问题标题】：Python for ArcGIS: add a text field to a shape file, then search one field and if meets a condition, update another fieldPython for ArcGIS：向形状文件添加文本字段，然后搜索一个字段，如果满足条件，则更新另一个字段
【发布时间】：2021-01-07 15:36:43
【问题描述】：

我正在自学 Python (2.7) for ArcGIS (10.8)。我有这个问题：

编写一个脚本，将文本字段添加到名为 road.shp 的要素类中 FERRY 并使用 YES 和 NO 值填充此字段，具体取决于 FEATURE 字段的值。

在尝试弄清楚并通过互联网检查后，我得到了这个脚本：

from arcpy
from arcpy import env
env.workspace = "C/esriPress/Python/Data/Exercise07/Results" # Set workspace
env.overwriteOutput = True   # overwriting outputs
fc = "roads.shp" # input feature class

newfield = "FERRY"  # new field to be created
fieldtype = "TEXT"  # type of the field that is going to be created
fieldname = arcpy.ValidateFieldName(newfield)  # to determine whether a specific name is valid or not
field_length = 3 # Lenght of th new field to be created
fieldlist = ListFields(fc)  # list the fields in 'fc', it returns a reference number of each object, not the object name.
fieldnames = [] # Create an empty list


# Check whether 'newfield' already exist or not; if not, create it
for field in fieldlist: # For each element in 'fieldlist'...
    fieldnames.append(field.name) #...add in the empty list 'fieldnames' the field name
if fieldname not in fieldnames: # if 'fieldname' don't exists in 'fiednames'...
    arcpy.AddField_management(fc, fieldname, fieldtype, field_length)  # ...Create 'fieldname' in 'fc' with length = 3
    print ("New field has been added")
else:
    print ("Field name already exists.")


# Search in the one field and update other field
fields = ['FEATURE', newfield]  # Create a list that contains the field we apply condition, and  the field we going to update
with arcpy.da.UpdateCursor(fc, fields) as cursor: # Setting the cursor; notice the cursor is made up of two fields
    for row in cursor: # For each row in cursor...
        if row[0] == "Ferry Crossing": #...if row in field 1 = "Ferry Crossing'...
            row[1] = "YES" #... Set that row in field 2 to 'Yes'
        else: # Otherwise...
            row[1] = "NO" # ....Set that row in field 2 to 'No'...
        cursor.updateRow(row) # Update cursor
print ("New field has been added" % newfield)

        else:
            row[1] = "NO"
        cursor.updateRow(row)
print ("Field name already exists" % newfield)

但是，当我在 PythonWin 2.7.16 中运行脚本时，我收到以下错误消息：

Failed to run script - syntax error - invalid syntax

我的脚本有什么问题？这是正确的方法吗？

【问题讨论】：

标签： arcgis arcpy

【解决方案1】：

您似乎有 2 个else 块和一个额外的cursor.updateRow(row)。因此，您的 print 语句没有正确缩进。尝试运行以下Update Cursor：

import arcpy

fc = '/path/to/your/geodatabase.gdb/feature_class'

# Add field
arcpy.AddField(fc, "FERRY", field_type = "TEXT")

# Update attributes based on a condition
# Note row[0] is "FEATURE" and row[1] is "FERRY"
with arcpy.da.UpdateCursor(fc, ["FEATURE", "FERRY"]) as cursor:
    for row in cursor:
        if row[0] == "ADD YOUR CONDITION HERE":
            row[1] = "YES"
        else:
            row[1] = "NO"
        cursor.updateRow(row)

【讨论】：