DataFrames | Vineeta Garg
DATAFRAMES
VIVA QUESTIONS
1. What is a DataFrame?
A DataFrame is a 2D labeled heterogeneous, data-mutable and size-mutable
array. The data in DataFrame is aligned in a tabular fashion in rows and
columns therefore has both a row and column labels.
2. What is a difference between DataFrames and Numpy Array?
The basic difference between a Numpy array and a Dataframe is that Numpy
array contains homogenous data while Dataframe contains heterogenous data.
3. How can we create customized labels in DataFrames?
The index and columns parameters can be used to change the default row and
column labels.
4. What happens when list of dictionaries is used to create a
DataFrame?
The dictionary keys are treated as column labels and row labels take default
values starting from zero. The values corresponding to each key are treated as
rows. The number of rows is equal to the number of dictionaries present in the
list.
5. What values are filled in the dataFrame for missing keys?
NaN
6. What happens when you try to add a column by the label which
already exist?
If the column already exists by the same label then the values of that column
are updated by the new values.
7. Name the method which is used to add a new row and column.
loc() method
8. Name the method which is used to delete a row/column?
DataFrame.drop() method
9. Name the method is used to rename the labels of rows and columns
in a DataFrame.
DataFrame.rename() method
The parameter axis=columns to reset column labels and axis=index to
reset row labels.
10. What is the difference between loc() and iloc() methods?
1
DATAFRAMES
VIVA QUESTIONS
1. What is a DataFrame?
A DataFrame is a 2D labeled heterogeneous, data-mutable and size-mutable
array. The data in DataFrame is aligned in a tabular fashion in rows and
columns therefore has both a row and column labels.
2. What is a difference between DataFrames and Numpy Array?
The basic difference between a Numpy array and a Dataframe is that Numpy
array contains homogenous data while Dataframe contains heterogenous data.
3. How can we create customized labels in DataFrames?
The index and columns parameters can be used to change the default row and
column labels.
4. What happens when list of dictionaries is used to create a
DataFrame?
The dictionary keys are treated as column labels and row labels take default
values starting from zero. The values corresponding to each key are treated as
rows. The number of rows is equal to the number of dictionaries present in the
list.
5. What values are filled in the dataFrame for missing keys?
NaN
6. What happens when you try to add a column by the label which
already exist?
If the column already exists by the same label then the values of that column
are updated by the new values.
7. Name the method which is used to add a new row and column.
loc() method
8. Name the method which is used to delete a row/column?
DataFrame.drop() method
9. Name the method is used to rename the labels of rows and columns
in a DataFrame.
DataFrame.rename() method
The parameter axis=columns to reset column labels and axis=index to
reset row labels.
10. What is the difference between loc() and iloc() methods?
1
