从文本中提取年龄值，在熊猫中创建新的列

I have a dataset as below:

我有一个数据集如下:

df=pd.DataFrame([["Sam is 5", 2000],["John is 3 years and 6 months",1200],["Jack is 4.5 years",7000],["Shane is 25 years old",2000]], columns = ['texts','amount'])

print(df)

    texts                          amount
0   Sam is 5                        2000
1   John is 3 years and 6 months    1200
2   Jack is 4.5 years               7000
3   Shane is 25 years old           2000
df=pd