pandas 如何创建 python 空数据帧,其中 df.empty 结果为 True
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how to create python empty dataframe where df.empty results in True
提问by Goofy Gert
How can I create an empty dataframe in python such that the test df.empty
results True
?
如何在 python 中创建一个空数据框以便测试df.empty
结果True
?
I tried this:
我试过这个:
df = pd.DataFrame(np.empty((1, 1)))
and df.empty
results in False
.
并df.empty
导致False
.
回答by Psidom
The simplest is pd.DataFrame()
:
最简单的是pd.DataFrame()
:
df = pd.DataFrame()
df.empty
# True
If you want create a data frame of specify number of columns:
如果要创建指定列数的数据框:
df = pd.DataFrame(columns=['A', 'B'])
df.empty
# True
Besides, an array of shape (1, 1)is not empty (it has one row), which is the reason you get empty = False, in order to create an empty array, it needs to be of shape (0, n):
此外,形状为(1, 1)的数组不为空(它有一行),这就是您得到empty = False的原因,为了创建一个空数组,它需要形状为(0, n):
df = pd.DataFrame(pd.np.empty((0, 3)))
df.empty
# True