打印 null 值的部分

Question

I am working with titanic dataset. I wonder how to show portion of null value from a train set.

Here is my code: `

train_count_of_missval_by_col = (train.isnull().sum())
print('----- all columns along with count of missing value')
print(train_count_of_missval_by_col)
print('----only columns which has missing values----')
print(train_count_of_missval_by_col[train_count_of_missval_by_col>0])
print('----only columns which has missing data to total observations----')
print(train_count_of_missval_by_col[train_count_of_missval_by_col>0]/train.shape[])`

Unfortunately, the last line of the code generate error. What to add / edit on the lastline so the code will work?

Answer 1

I am not sure if there is a specific operation for this. info() shows you the raw # and tells you the total rows but there are no parameters for the %. Also .info() returns as a None type object, so you can't access any data from that object.

I would suggest looping through the column and returning the # null divided by total rows with df[col].isnull().sum() / df.shape[0] * 100 and printing out the output in a formatted string as such:

d = {'Col1': [np.nan, 6, np.nan, 2, np.nan],
     'Col2': [np.nan, 3, 5, np.nan, 9],
     'Col3': [2, 1, 8, np.nan, 9]}
df = pd.DataFrame(d)
for col in df.columns:
    print(col, f'{df[col].isnull().sum() / df.shape[0] * 100} % NULL')

Col1 60.0 % NULL
Col2 40.0 % NULL
Col3 20.0 % NULL