检查对象是否是python中的列表列表?

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时间:2020-08-18 22:23:49  来源:igfitidea点击:

Check if object is list of list in python?

pythonlist

提问by Nilesh Agrawal

Is there any ways we can detect if an object is list in python using type(obj)--> list.

有什么方法可以使用type(obj)-->检测对象是否在python中列出list

But how can we detect if the object is list of list of the form as:

但是我们如何检测对象是否是表单列表的列表:

[['a','b']['a','b'][][]]

回答by Blender

If you want to make sure that everyitem in your list is a list, you could do something like this:

如果您想确保列表中的每个项目都是一个列表,您可以执行以下操作:

if all(isinstance(i, list) for i in lst):
    # All of the items are lists
  • isinstance(i, list)is the better way of writing type(i) == type(list)or type(i) == list).
  • all()returns Trueif all of the items in the sequence are True. It'll return Falseif any aren't True.
  • isinstance(i, list)是更好的写作方式type(i) == type(list)还是type(i) == list).
  • all()True如果序列中的所有项目都是 ,则返回TrueFalse如果没有,它会返回True

回答by Martijn Pieters

Use isinstance()to check for a specific type:

使用isinstance()检查特定类型:

>>> isinstance([], list)
True

Use all()to test if allelements are of a certain type:

使用all()如果测试所有的元素是某种类型的:

all(isinstance(elem, list) for elem in list_of_lists)

all()short-circuits; if any of the tests returns False, the loop is terminated and Falseis returned. Only if all but one element returns Truedoes all()need to examine every element of the iterable.

all()短路;如果任何测试返回False,则循环终止并False返回。只有当除一个元素之外的所有元素都返回时True,才all()需要检查可迭代对象的每个元素。