Python Pandas 面试题与答案

问题 41. What is the purpose of the crosstab() function in Pandas?

crosstab() computes a simple cross-tabulation of two (or more) factors.

Example:

pd.crosstab(df['factor1'], df['factor2'])

问题 42. How do you apply a custom function to each element in a Pandas DataFrame?

Use the applymap() function. df.applymap(my_function)

问题 43. Explain the concept of method chaining in Pandas.

Method chaining is a way of applying multiple operations on a DataFrame in a single line of code.

Example:

df.dropna().mean()

问题 44. What is the purpose of the pipe() function in Pandas?

pipe() is used to apply a function to a DataFrame using method chaining.

Example:

df.pipe(my_function).dropna()

问题 45. How can you create a Pandas DataFrame from a dictionary of Series or dictionaries?

Use the pd.DataFrame() constructor. df = pd.DataFrame({'column1': series1, 'column2': series2})