To rank the rows of Pandas DataFrame we can use the DataFrame.rank() method which returns a rank of every respective index of a series passed. The rank is returned on the basis of position after sorting.

The following program illustrates how to rank a DataFrame data

# import the required packages import pandas as pd # Define the dictionary for converting to dataframe movies = {'Name': ['The Godfather', 'Bird Box', 'Fight Club'], 'Year': ['1972', '2018', '1999'], 'Rating': ['9.2', '6.8', '8.8']} df = pd.DataFrame(movies) print(" Before ranking") print(df) # Create a column Rating_Rank which contains # the rank of each movie based on rating df['Rating_Rank'] = df['Rating'].rank(ascending = 1) # Set the index to newly created column, Rating_Rank df = df.set_index('Rating_Rank') print("After Ranking") print(df)

The following is the output for above program

Sorting

There are two kinds of sorting available in Pandas. They are −

By label

By Actual Value

Let us consider an example with an output.

import pandas as pd import numpy as np unsorted_df=pd.DataFrame(np.random.randn(10,2),index=[1,4,6,2,3,5,9,8,0,7], columns=['col2','col1']) print(unsorted_df)

Output:-

**By Label **

Using the sort_index() method, by passing the axis arguments and the order of sorting, DataFrame can be sorted. By default, sorting is done on row labels in ascending order.

import pandas as pd import numpy as np unsorted_df = pd.DataFrame(np.random.randn(10,2),index=[1,4,6,2,3,5,9,8,0,7], columns = ['col2','col1']) sorted_df=unsorted_df.sort_index() print(sorted_df)

Output:-

**By Value**

Like index sorting, sort_values() is the method for sorting by values. It accepts a by argument which will use the column name of the DataFrame with which the values are to be sorted.

The following illustrates how to sort data by value

import pandas as pd import numpy as np unsorted_df = pd.DataFrame({'col1':[2,1,1,1],'col2':[1,3,2,4]}) sorted_df = unsorted_df.sort_values(by='col1') print(sorted_df)

Output:-

## 0 comments:

## Post a Comment

Note: only a member of this blog may post a comment.