Pandas的基本用法(三)——设置数据

来源：互联网发布：淘宝店铺装修在线制作编辑：程序博客网时间：2024/06/05 18:15
文章作者：Tyan
博客：noahsnail.com | CSDN | 简书
本文主要是关于pandas的一些基本用法。
#!/usr/bin/env python# _*_ coding: utf-8 _*_import pandas as pdimport numpy as np# Test 1# 定义数据dates = pd.date_range('20170101', periods = 6)print datesdf = pd.DataFrame(np.arange(24).reshape((6, 4)), index = dates, columns = ['A', 'B', 'C', 'D'])print df# Test 1 resultDatetimeIndex(['2017-01-01', '2017-01-02', '2017-01-03', '2017-01-04',               '2017-01-05', '2017-01-06'],              dtype='datetime64[ns]', freq='D')             A   B   C   D2017-01-01   0   1   2   32017-01-02   4   5   6   72017-01-03   8   9  10  112017-01-04  12  13  14  152017-01-05  16  17  18  192017-01-06  20  21  22  23# Test 2# 设置df[2,2]为100df.iloc[2, 2] = 100print df# loc设置值df.loc['20170102', 'C'] = 999print df# 根据条件设置值df[df.A > 8] = 0print df# 根据ix设置值df.ix[[0, 2],  ['A', 'C']] = 888print df# 限定设置区域df.B[df.B == 0] = 6print df # Test 2 result             A   B    C   D2017-01-01   0   1    2   32017-01-02   4   5    6   72017-01-03   8   9  100  112017-01-04  12  13   14  152017-01-05  16  17   18  192017-01-06  20  21   22  23             A   B    C   D2017-01-01   0   1    2   32017-01-02   4   5  999   72017-01-03   8   9  100  112017-01-04  12  13   14  152017-01-05  16  17   18  192017-01-06  20  21   22  23            A  B    C   D2017-01-01  0  1    2   32017-01-02  4  5  999   72017-01-03  8  9  100  112017-01-04  0  0    0   02017-01-05  0  0    0   02017-01-06  0  0    0   0              A  B    C   D2017-01-01  888  1  888   32017-01-02    4  5  999   72017-01-03  888  9  888  112017-01-04    0  0    0   02017-01-05    0  0    0   02017-01-06    0  0    0   0              A  B    C   D2017-01-01  888  1  888   32017-01-02    4  5  999   72017-01-03  888  9  888  112017-01-04    0  6    0   02017-01-05    0  6    0   02017-01-06    0  6    0   0# Test 3# 添加一列df['F'] = Noneprint df# 添加一列df['E'] = pd.Series([1, 2, 3, 4, 5, 6], index = dates)print df# Test 3 result              A  B    C   D     F2017-01-01  888  1  888   3  None2017-01-02    4  5  999   7  None2017-01-03  888  9  888  11  None2017-01-04    0  6    0   0  None2017-01-05    0  6    0   0  None2017-01-06    0  6    0   0  None              A  B    C   D     F  E2017-01-01  888  1  888   3  None  12017-01-02    4  5  999   7  None  22017-01-03  888  9  888  11  None  32017-01-04    0  6    0   0  None  42017-01-05    0  6    0   0  None  52017-01-06    0  6    0   0  None  6
0 0