Python Pandas 面试题与答案

问题 46. Explain the purpose of the stack() and unstack() functions in Pandas.

stack() is used to pivot the columns of a DataFrame to the rows. unstack() does the reverse operation.

Example:

df.stack()

问题 47. What is the purpose of the to_excel() function in Pandas?

to_excel() is used to write a DataFrame to an Excel file.

Example:

df.to_excel('output.xlsx', index=False)

问题 48. How do you calculate the correlation matrix for a Pandas DataFrame?

Use the corr() function. df.corr()