This quiz on Handling Missing Data tests your knowledge of key methods and techniques used to identify, manage, and resolve missing values in datasets.
Question 1
Which method is used to fill missing values with the mean of a column in Pandas?
dropna()
fillna()
mean()
interpolate()
Question 2
What will be the output of the following code?
import pandas as pd
import numpy as np
data = {'A': [1, 2, np.nan, 4], 'B': [np.nan, 2, 3, 4]}
df = pd.DataFrame(data)
result = df.isnull().sum()
print(result)
A 1
B 1
dtype: int64
A 2
B 2
dtype: int64
A 1
B 2
dtype: int64
A 2
B 1
dtype: int64
Question 3
Which of the following methods is suitable for forward-filling missing data in a DataFrame?
`fillna(method='ffill')`
`fillna(method='bfill')`
`interpolate()
`dropna()`
Question 4
What is the result of the following code?
import pandas as pd
import numpy as np
data = {'A': [1, np.nan, 3], 'B': [4, 5, np.nan]}
df = pd.DataFrame(data)
df.dropna(axis=1, how='any', inplace=True)
print(df)
Empty DataFrame
A B
0 1 4
A
0 1
2 3
Empty DataFrame
Columns: []
Index: [0, 1, 2]
Question 5
What does the interpolate() method do when handling missing values in Pandas?
Drops rows with missing values
Replaces missing values using a linear interpolation method
Fills missing values with a fixed value
None of the above
Question 6
What is the output of this code snippet?
import pandas as pd
import numpy as np
data = {'A': [np.nan, 2, np.nan, 4], 'B': [1, np.nan, 3, 4]}
df = pd.DataFrame(data)
df['A'] = df['A'].fillna(df['A'].mean())
print(df)
A B
0 3.0 1.0
1 2.0 NaN
2 3.0 3.0
3 4.0 4.0
A B
0 4.0 1.0
1 2.0 NaN
2 4.0 3.0
3 4.0 4.0
A B
0 NaN 1.0
1 2.0 NaN
2 NaN 3.0
3 4.0 4.0
A B
0 NaN NaN
1 NaN NaN
2 NaN NaN
3 NaN NaN
Question 7
Which method permanently removes rows with missing values?
dropna()
fillna()
isnull()
notnull()
Question 8
In the following code, how many rows will remain after execution?
import pandas as pd
import numpy as np
data = {'A': [1, np.nan, 3], 'B': [4, np.nan, np.nan]}
df = pd.DataFrame(data)
df.dropna(how='all', inplace=True)
0
1
3
2
Question 9
What will the following code output?
import pandas as pd
import numpy as np
data = {'A': [np.nan, 2, 3], 'B': [4, np.nan, 6]}
df = pd.DataFrame(data)
df.fillna({'A': 0, 'B': 1}, inplace=True)
print(df)
A B
0 0.0 4.0
1 2.0 1.0
2 3.0 6.0
A B
0 NaN 4.0
1 2.0 NaN
2 3.0 6.0
A B
0 NaN 1.0
1 2.0 1.0
2 3.0 6.0
A B
0 0.0 1.0
1 2.0 1.0
2 3.0 6.0
Question 10
Which of the following is true about dropna(subset=[columns])?
Removes all rows with missing values across the specified subset of columns
Removes rows only if all specified columns have missing values
Removes rows only if no columns in the subset have missing values
None of the above
There are 10 questions to complete.