根据条件从 pandas DataFrame 中删除行

Question

我是 pandas 的新手，所以请原谅新手的问题！

我有以下代码；

import pandas as pd

pet_names = ["Name","Species"
"Jack","Cat"
"Jill","Dog"
"Tom","Cat"
"Harry","Dog"
"Hannah","Dog"]

df = pd.DataFrame(pet_names)

df = df[df['Species']!='Cat']

print(df)

我想删除“物种”列中所有包含“猫”的行，留下所有的狗。我该怎么做呢？不幸的是，此代码当前返回错误。

Answer 1

一般boolean indexing

df[df['Species'] != 'Cat']
# df[df['Species'].ne('Cat')]

  Index    Name Species
1     1    Jill     Dog
3     3   Harry     Dog
4     4  Hannah     Dog

---

df.query

df.query("Species != 'Cat'")

  Index    Name Species
1     1    Jill     Dog
3     3   Harry     Dog
4     4  Hannah     Dog

有关pd.eval() 系列函数、它们的特性和用例的信息，请访问Dynamic Expression Evaluation in pandas using pd.eval()。

---

df.isin

df[~df['Species'].isin(['Cat'])]

  Index    Name Species
1     1    Jill     Dog
3     3   Harry     Dog
4     4  Hannah     Dog