数据源：链接: https://pan.baidu.com/s/1EFqJFXf70t2Rubkh6D19aw 提取码: syqg
数据源示例：
探索Iris纸鸢花数据
步骤1 导入必要的库
import pandas as pd
import numpy as np
步骤2 数据集地址
path1='pandas_exercise\exercise_data\iris.csv'
步骤3 将数据集存成变量iris
iris=pd.read_csv(path1)
print(iris.head())
步骤4 创建数据框的列名称
iris=pd.read_csv(path1,names = ['sepal_length','sepal_width', 'petal_length', 'petal_width', 'class'])
print(iris.head())
步骤5 数据框中有缺失值吗？
print(pd.isnull(iris).sum())
步骤6 将列petal_length的第10到19行设置为缺失值
iris.iloc[10:20,2:3]=np.nan
print(iris.head(20))
步骤7 将缺失值全部替换为1.0
iris.fillna(1,inplace=True)
print(iris.head(20))
步骤8 删除列class
del iris['class']
步骤9 将数据框前三行设置为缺失值
iris.iloc[:3,:]=np.nan
print(iris.head())
步骤10 删除有缺失值的行
iris=iris.dropna(how='any')
步骤11 重新设置索引
iris=iris.reset_index(drop=True)
print(iris.head())
# 步骤3
5.1 3.5 1.4 0.2 Iris-setosa
0 4.9 3.0 1.4 0.2 Iris-setosa
1 4.7 3.2 1.3 0.2 Iris-setosa
2 4.6 3.1 1.5 0.2 Iris-setosa
3 5.0 3.6 1.4 0.2 Iris-setosa
4 5.4 3.9 1.7 0.4 Iris-setosa
# 步骤4
sepal_length sepal_width petal_length petal_width class
0 5.1 3.5 1.4 0.2 Iris-setosa
1 4.9 3.0 1.4 0.2 Iris-setosa
2 4.7 3.2 1.3 0.2 Iris-setosa
3 4.6 3.1 1.5 0.2 Iris-setosa
4 5.0 3.6 1.4 0.2 Iris-setosa
# 步骤5
sepal_length 0
sepal_width 0
petal_length 0
petal_width 0
class 0
dtype: int64
# 步骤6
sepal_length sepal_width petal_length petal_width class
0 5.1 3.5 1.4 0.2 Iris-setosa
1 4.9 3.0 1.4 0.2 Iris-setosa
2 4.7 3.2 1.3 0.2 Iris-setosa
3 4.6 3.1 1.5 0.2 Iris-setosa
4 5.0 3.6 1.4 0.2 Iris-setosa
5 5.4 3.9 1.7 0.4 Iris-setosa
6 4.6 3.4 1.4 0.3 Iris-setosa
7 5.0 3.4 1.5 0.2 Iris-setosa
8 4.4 2.9 1.4 0.2 Iris-setosa
9 4.9 3.1 1.5 0.1 Iris-setosa
10 5.4 3.7 NaN 0.2 Iris-setosa
11 4.8 3.4 NaN 0.2 Iris-setosa
12 4.8 3.0 NaN 0.1 Iris-setosa
13 4.3 3.0 NaN 0.1 Iris-setosa
14 5.8 4.0 NaN 0.2 Iris-setosa
15 5.7 4.4 NaN 0.4 Iris-setosa
16 5.4 3.9 NaN 0.4 Iris-setosa
17 5.1 3.5 NaN 0.3 Iris-setosa
18 5.7 3.8 NaN 0.3 Iris-setosa
19 5.1 3.8 NaN 0.3 Iris-setosa
# 步骤7
sepal_length sepal_width petal_length petal_width class
0 5.1 3.5 1.4 0.2 Iris-setosa
1 4.9 3.0 1.4 0.2 Iris-setosa
2 4.7 3.2 1.3 0.2 Iris-setosa
3 4.6 3.1 1.5 0.2 Iris-setosa
4 5.0 3.6 1.4 0.2 Iris-setosa
5 5.4 3.9 1.7 0.4 Iris-setosa
6 4.6 3.4 1.4 0.3 Iris-setosa
7 5.0 3.4 1.5 0.2 Iris-setosa
8 4.4 2.9 1.4 0.2 Iris-setosa
9 4.9 3.1 1.5 0.1 Iris-setosa
10 5.4 3.7 1.0 0.2 Iris-setosa
11 4.8 3.4 1.0 0.2 Iris-setosa
12 4.8 3.0 1.0 0.1 Iris-setosa
13 4.3 3.0 1.0 0.1 Iris-setosa
14 5.8 4.0 1.0 0.2 Iris-setosa
15 5.7 4.4 1.0 0.4 Iris-setosa
16 5.4 3.9 1.0 0.4 Iris-setosa
17 5.1 3.5 1.0 0.3 Iris-setosa
18 5.7 3.8 1.0 0.3 Iris-setosa
19 5.1 3.8 1.0 0.3 Iris-setosa
# 步骤9
sepal_length sepal_width petal_length petal_width
0 NaN NaN NaN NaN
1 NaN NaN NaN NaN
2 NaN NaN NaN NaN
3 4.6 3.1 1.5 0.2
4 5.0 3.6 1.4 0.2
# 步骤11
sepal_length sepal_width petal_length petal_width
0 4.6 3.1 1.5 0.2
1 5.0 3.6 1.4 0.2
2 5.4 3.9 1.7 0.4
3 4.6 3.4 1.4 0.3
4 5.0 3.4 1.5 0.2
