pandas 从数据框列检查字符串是否为 nan
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时间：2020-09-13 22:21:50 来源:igfitidea点击:
from a dataframe column check if a string is nan
提问by richie
From a dataframe when I print data['words'].valuesI get,
从我打印时的数据框中data['words'].values得到，
['from' 'fairest' 'creatures' 'we' 'desire' 'increase' nan 'that' 'thereby']
When I loop through like this how do I identify if the value is nan?
当我这样循环时，如何确定值是否为 nan？
for w in data['words'].values:
check if w is nan ????
回答by EdChum
Use the pandas method isnullto test:
使用pandas方法isnull测试：
In [45]:
df = pd.DataFrame({'words':['from', 'fairest', 'creatures' ,'we' ,'desire', 'increase' ,nan ,'that' ,'thereby']})
df
Out[45]:
words
0 from
1 fairest
2 creatures
3 we
4 desire
5 increase
6 NaN
7 that
8 thereby
In [46]:
pd.isnull(df['words'])
Out[46]:
0 False
1 False
2 False
3 False
4 False
5 False
6 True
7 False
8 False
Name: words, dtype: bool
回答by Max Kleiner
the question was about the if:
问题是关于如果：
for i in range(150,160):
if (pd.isnull(df['Text'][i])):
print('is null')
or count all NaN:
或计算所有 NaN：
cnt=0
for i in range(len(dframe)):
if (pd.isnull(dframe['Description'][i])):
cnt+=1
