访问名为"class"的列时出现SyntaxError.在pandas DataFrame中 [英] SyntaxError when accessing column named "class" in pandas DataFrame

问题描述

我有一个名为'dataset'的pandas DataFrame，它包含一个名为'class'的列

I have pandas DataFrame named 'dataset' and it contains a column named 'class'

执行以下行时，出现SyntaxError:语法无效

when I execute the following line I get SyntaxError: invalid syntax

print("Unique values in the Class column:", dataset.class.unique())

它适用于其他列名，但不适用于'class'

It works for another column names but not working with 'class'

如何在大熊猫中使用关键字作为列名?

How to use a keyword as column name in pandas ?

推荐答案

class是python中的关键字.经验法则:每当处理不能在python中用作有效变量名的列名时，都必须使用方括号表示法来访问:dataset['class'].unique().

class is a keyword in python. A rule of thumb: whenever you're dealing with column names that cannot be used as valid variable names in python, you must use the bracket notation to access: dataset['class'].unique().

当然，这里有例外，但是它们不利于您的偏爱.例如，min/max是python中的有效变量名(即使它隐藏了内置函数).但是，对于大熊猫，您不能使用属性访问"表示法来引用这样的命名列.文档中已列举了更多此类例外.

There are, of course, exceptions here, but they work against your favour. For example, min/max is a valid variable name in python (even though it shadows builtins). In the case of pandas, however, you cannot refer to such a named column using the Attribute Access notation. There are more such exceptions, they're enumerated in the documentation.

A good place to begin with further reading is the documentation on Attribute Access (specifically, the red Warning box).

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