总结一下
索引问题
1.1 认识索引
先创建一个简单的 DataFrame。
myList = [['a', 10, 1.1],
['b', 20, 2.2],
['c', 30, 3.3],
['d', 40, 4.4]]
df1 = pd.DataFrame(data = myList)
print(df1)
print(df1.columns)
[out]:
RangeIndex(start=0, stop=3, step=1)
[out]:
char int float
one a 10 1.1
two b 20 2.2
three c 30 3.3
four d 40 4.4
输出此时的行索引和列索引:
print(df2.index)
[out]:
Index(['one', 'two', 'three', 'four'], dtype='object')
type(df2[['char']])
[out]:pandas.core.frame.DataFrame
注意直接使用 df2[0] 取某一列会报错,除非 columns是由下标索引组成的,比如 df1那个样子, df1[0] 就不会报错。
`python
print(df1[0])
[out]:
0 a
1 b
2 c
3 d
Name: 0, dtype: object
print(df2.loc[[‘one’, ‘three’]])
[out]:
char int float
one a 10 1.1
three c 30 3.3
print(df2.iloc[[0, 2]])
[out]:
char int float
one a 10 1.1
three c 30 3.3
Original: https://blog.csdn.net/weixin_46713695/article/details/125959391
Author: 赵孝正
Title: python中Pandas之DataFrame索引、选取数据
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