Tilde登录python数据框 [英] Tilde sign in python dataframe

问题描述

我是python的新手，遇到了一个代码段.

Im new to python and came across a code snippet.

df = df[~df['InvoiceNo'].str.contains('C')]

如果我能知道在此情况下代字号使用了什么，那将是非常有义务的吗?

Would be much obliged if I could know whats the tilde signs usage in this context ?

推荐答案

这意味着按位不对，将布尔掩码反转-将False s转换为True s，将True s转换为False s.

It means bitwise not, inversing boolean mask - Falses to Trues and Trues to Falses.

示例:

df = pd.DataFrame({'InvoiceNo': ['aaC','ff','lC'],
                   'a':[1,2,5]})
print (df)
  InvoiceNo  a
0       aaC  1
1        ff  2
2        lC  5

#check if column contains C
print (df['InvoiceNo'].str.contains('C'))
0     True
1    False
2     True
Name: InvoiceNo, dtype: bool

#inversing mask
print (~df['InvoiceNo'].str.contains('C'))
0    False
1     True
2    False
Name: InvoiceNo, dtype: bool

通过 boolean indexing 进行过滤:

df = df[~df['InvoiceNo'].str.contains('C')]
print (df)
  InvoiceNo  a
1        ff  2

所以输出是DataFrame的所有行，在InvoiceNo列中不包含C.

So output is all rows of DataFrame, which not contains C in column InvoiceNo.

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