在熊猫数据框中排序行
原文:https://www.geeksforgeeks.org/sorting-row-in-pandas-data frame/
Pandas DataFrame 是一个二维可变大小的、潜在异构的表格数据结构，带有标签轴(行和列)。在处理数据时，我们经常需要对行和列进行某些操作。
让我们看看如何对熊猫数据框中的行进行排序。
代码#1: 按科学排序行
# import modules
import pandas as pd
# create dataframe
data = {'name': ['Simon', 'Marsh', 'Gaurav', 'Alex', 'Selena'],
'Maths': [8, 5, 6, 9, 7],
'Science': [7, 9, 5, 4, 7],
'English': [7, 4, 7, 6, 8]}
df = pd.DataFrame(data)
# Sort the dataframe’s rows by Science,
# in descending order
a = df.sort_values(by ='Science', ascending = 0)
print("Sorting rows by Science:\n \n", a)
Output:
Sorting rows by Science:
English Maths Science name
1 4 5 9 Marsh
0 7 8 7 Simon
4 8 7 7 Selena
2 7 6 5 Gaurav
3 6 9 4 Alex
代码#2: 先按数学再按英语对行进行排序。
# import modules
import pandas as pd
# create dataframe
data = {'name': ['Simon', 'Marsh', 'Gaurav', 'Alex', 'Selena'],
'Maths': [8, 5, 6, 9, 7],
'Science': [7, 9, 5, 4, 7],
'English': [7, 4, 7, 6, 8]}
df = pd.DataFrame(data)
# Sort the dataframe’s rows by Maths
# and then by English, in ascending order
b = df.sort_values(by =['Maths', 'English'])
print("Sort rows by Maths and then by English: \n\n", b)
Output:
Sort rows by Maths and then by English:
English Maths Science name
1 4 5 9 Marsh
2 7 6 5 Gaurav
4 8 7 7 Selena
0 7 8 7 Simon
3 6 9 4 Alex
代码#3: 如果你想先缺值。
import pandas as pd
# create dataframe
data = {'name': ['Simon', 'Marsh', 'Gaurav', 'Alex', 'Selena'],
'Maths': [8, 5, 6, 9, 7],
'Science': [7, 9, 5, 4, 7],
'English': [7, 4, 7, 6, 8]}
df = pd.DataFrame(data)
a = df.sort_values(by ='Science', na_position ='first' )
print(a)
Output:
English Maths Science name
3 6 9 4 Alex
2 7 6 5 Gaurav
0 7 8 7 Simon
4 8 7 7 Selena
1 4 5 9 Marsh
由于本例中没有缺失值，这将产生与上面相同的输出，但按升序排序。
