Python中Pandas库提供的函数pd.DataFrame的基本用法

import pandas as pd
df = pd.DataFrame()
print(df)
# 运行结果
'''
Empty DataFrame
Columns: []
Index: []
'''

import pandas as pd
data = [['Alice', 25], ['Bob', 30], ['Charlie', 35]]
df = pd.DataFrame(data, columns=['Name', 'Age'])
print(df)
# 运行结果
'''
      Name  Age
0    Alice   25
1      Bob   30
2  Charlie   35
'''

import pandas as pd
data = {'Name': ['Alice', 'Bob', 'Charlie'], 'Age': [25, 30, 35]}
df = pd.DataFrame(data)
print(df)
# 运行结果
'''
      Name  Age
0    Alice   25
1      Bob   30
2  Charlie   35
'''

import pandas as pd
data = {'Name': ['Alice', 'Bob', 'Charlie'], 'Age': [25, 30, 35]}
df = pd.DataFrame(data)
a = df['Name']  # 获取 'Name' 列的数据
b = df.loc[0]    # 获取第一行的数据
print(a)
print(b)
# 运行结果
'''
0      Alice
1        Bob
2    Charlie
Name: Name, dtype: object
Name    Alice
Age        25
Name: 0, dtype: object
'''

import pandas as pd
data = {'Name': ['Alice', 'Bob', 'Charlie'], 'Age': [25, 30, 35]}
df = pd.DataFrame(data)
a = df['Age'].mean()  # 计算 'Age' 列的平均值
b = df.sort_values(by='Age', ascending=False)  # 按 'Age' 列排序,ascending=True是从小到大，ascending=False是从大到小
print(a)
print(b)
# 运行结果
'''
30.0
      Name  Age
2  Charlie   35
1      Bob   30
0    Alice   25
'''

import pandas as pd
data = {'Name': ['Alice', 'Bob', 'Charlie'], 'Age': [25, 30, 35]}
df = pd.DataFrame(data)
a = df.head(2)     # 查看前几行数据，df.head()默认为前5行
b = df.tail(2)    # 查看后3行数据
print(a)
print(b)
# 运行结果
'''
    Name  Age
0  Alice   25
1    Bob   30
      Name  Age
1      Bob   30
2  Charlie   35
'''

import pandas as pd
data = {'Name': ['Alice', 'Bob', 'Charlie'], 'Age': [25, 30, 35]}
df = pd.DataFrame(data)
c=df.describe()  # 生成数据的统计摘要信
print(c)
# 运行结果
'''
Age
count   3.0
mean   30.0
std     5.0
min    25.0
25%    27.5
50%    30.0
75%    32.5
max    35.0
'''