正在dataframe中获取NaN值，但不确定原因

Question

我正在尝试创建一个从github url绘制的数据帧。然后，数据帧将github文件中的Age列排序到新的数据帧中，Age_12列的Age值介于（1-12）之间，Age_TEEN列的Age值介于（13-19）之间。但是，当我将代表年龄12和年龄青少年值的数据分配给新数据框中的列时，我最终得到了它们的NaN值？我试着切换列的位置，年龄12有时会产生正确的值，但另一个不会，反之亦然

这是我的密码：

#Reads url for Github
url = 'https://raw.githubusercontent.com/wesm/pydata-book/2nd-edition/datasets/titanic/train.csv'
#Creates dataframe from Raw Github Link 
data = pd.read_csv(url, error_bad_lines=False)



AGE_12 = data[data['Age'].between(1,12)]
AGE_TEEN = data[data['Age'].between(13,19)]


pasUpto19 = pd.DataFrame()
pasUpto19 = pasUpto19.assign(PCLASS=data['Pclass'],AGE_12=AGE_12['Age'],AGE_TEEN=AGE_TEEN['Age'])
print(pasUpto19)

它的输出是：

     PCLASS  AGE_12  AGE_TEEN
0         3     NaN       NaN
1         1     NaN       NaN
2         3     NaN       NaN
3         1     NaN       NaN
4         3     NaN       NaN
..      ...     ...       ...
886       2     NaN       NaN
887       1     NaN      19.0
888       3     NaN       NaN
889       1     NaN       NaN
890       3     NaN       NaN

如果我做了一些愚蠢的事情，请提前道歉，我对python和使用熊猫非常陌生

Answer 1

pasUpto19 = pasUpto19.dropna(axis=0, how='all')将从新数据帧中删除所有nan值