RogerDunnGIS的最新贡献

我的尝试块通常是这样的:eddy = arcpy.da.Editor(myWorkspace) try: eddy。startEditing(False, True) eddy.startOperation()尝试:与arcpy.da。UpdateCursor(in_table, fields, query) as uCursor: for row in uCursor: # do something uCursor. updaterow (row) del uCursor eddy. stopoperation () eddy. stopediting (True) except: eddy. abortoperation () eddy. stopediting (False) finally: del eddy ．.．查看更多

我说得太早了。这是基于你所说的，对我有用的代码。给定地图中的一个层，我可以这样做:tableName = desc["catalogPath"] fields = ["OBJECTID"， "COMMENT"] query = "OBJECTID in({0})"。format("， ".join((str(objId) for objId in objectIds))) eddy = arcpy.da.Editor(sdeFileName)startEditing(True, True) eddy.startOperation() with arcpy.da。UpdateCursor(tableName, fields, query) as uCursor: for row in uCursor: row[1] = "Test Comment" uCursor. updaterow (row) del uCursor eddy. stopoperation () eddy. stopediting (True) del eddy这将修改一个不属于选择的行!爱它! ．.．查看更多

好的，但是如果layername是一个层的名称，因为它出现在目录中，它将有一个选择，我需要忽略各种游标。 ．.．查看更多

这确实适用于我，但我没有把它标记为解决方案。是谁干的，又是怎么发生的? ．.．查看更多

我曾经看到过这些属性，但文档似乎表明它们是用于警告和错误消息的。谢谢你的发帖。 ．.．查看更多

下面是另一个练习:在这里，我们创建一个元组，其中包含两个新字符串，作为切片操作的结果。由于两个字符串都保留在内存中，#都不会被释放，它们的id也会不同。Orange_slices = (s[:3]， s[:5]) id(Orange_slices [0]) 1448227048496 id(Orange_slices [1]) 1448234245616 ．.．查看更多

如果点和线在同一地理数据库和同一地理数据集中，那么它们可能具有相同的XY公差，这很好。如果我说错了请纠正我，但我所理解的XY公差是定义一个地图单位的测量中可以容纳多少个整数。数据库更喜欢存储和查询整数，因此XY公差是将这些整数分解为我们在地图、属性表、JSON几何图形等上看到的浮点数。例如，如果在Foot_US中创建了一个XY公差为0.0032808333333333333的特征类，这意味着数据库的真实值1000将返回给软件和用户为3.28083333333333 US Feet。double/float值612,718.82934将被存储在数据库中，作为大约186,757,073的整数。各位，我说的对吗?如果你的点和烟花不在同一个地理数据库或地理数据集中，那么XY公差的差异可能就是问题所在。地球几何并不总是像平面几何那样。在GIS中使用x和y这样的术语，而实际上，y轴在几千英里后会聚到一点，这仍然让我感到困扰。地球的实际形状仍然是一个谜，地震和地震发生的所有变化，不断移动的构造板块，海洋爬上海岸，在晚上退缩。 As much as I want my GIS to be like graph paper, it just isn't. ．.．查看更多

我已经做了很多年的ArcGIS Python程序员，我从来没有真正需要id()函数或is操作符来完成实际工作。实际上，我只关心相等(==)。既然你只是在尝试，我想这就足够了，但这可能不是一个你不需要深入研究的兔子洞。这就是上面代码中发生的事情。打印语句调用时使用逗号，这意味着每个参数#将被计算，从左到右一次一个。# 2) s [3:] id # 3)产生一个新的字符串,字符串传递给id的函数,它返回它的内存地址# 4)内存地址进入一个新的int对象# 5)字符串不再需要,所以它被释放# 6)5:产生一个新的字符串,再利用空闲内存# 7)字符串传递给id的函数,它返回它的内存地址#内存地址进入一个新的int对象# 9)字符串不再需要,#两个对象在存活时具有相同的id，因此打印出#相同的id。print(id(s[3:])， id(s[5:])) #与上面类似，每个参数从左到右计算。这一次，print只有一个参数，但是参数#是一个运算符的结果。运算符从左到右解析它的操作数#。 # Follow steps 1 through 9, paying attention to 4) and 8). # Int objects are equal to each other if they have the same value # so True is returned to the print statement. print(id(s[3:])==id(s[5:])) # 1) The print statement is called with one parameter, as evidenced by # its lack of commas # 2) The print statement's only parameter is the result of the is operator # 3) The is operator evaluates its operands from left to right # 4) s[3:] produces a new string with an id # Note that this new string is still needed for the is operator, so it # is not freed. It hangs out in memory # 6) s[5:] produces a new string with an id # This new string is also needed for the is operator, so it is not freed either # 7) The is operator now compares the identity of both living strings, # sees that they aren't equal, and returns False in both instances. print(s[3:] is s[5:]) print(s[3:] is s[3:]) Now, to address @DanPatterson 's post: s = 'a string' # Since there are no print statements, I'm not sure how he got results # that are in the comments. Perhaps, if run in a terminal, or at different # times, the new strings did not reuse recently freed memory. id(s) # 2625510363760 id(s[:3]) # 2625512614384 id(s[:3]) # 2625512614000 id(s[:3]) # 2625512908528 # 1) The is operator evaluates its operands from left to right # 2) s[:3] creates a new string with an id # 3) The id function is called, returning a new int object # 4) The new string is freed, releasing its memory # 5) s[:3] creates a new string with an id. This may or may # not have been created in the same memory space as 1) was # 6) The id function is called, returning a new int object # 7) The is operator attempts to establish identity on the # two ints that were returned, which have not been freed. # The ints are different objects, so is returns False. id(s[:3]) is id(s[:3]) # False # This is actually the easiest to explain. Dan could have # typed id(10>7), id("h" in "PYTHON".lower()), or id(5!=7) # and still gotten the same memory address. # What he is doing is grabbing the id of the result of the # _equality_ operator. Those results are bools. The values # True and False are global objects of type bool. Because # they are objects, they each have an id. Comparator operators # don't create new instances of type bool, but simply # use the existing ones. id(id(s[:3]) == id(s[:3])) # 140711459289192 id(s[:3] == s[:3]) # 140711459289192 ．.．查看更多