Python财务分析-Pandas基础

Love The Way You Lie 2023-07-24 03:21 100阅读 0赞

> 以下代码按顺序执行，在ipython中执行，如果再PyCharm中，按包调用即可，如 `Series([1, 2, 3, 4, 5], index=labels)`，使用 `pd.Series([1, 2, 3, 4, 5], index=labels)`，pd为导入pandas时的昵称。

## 数据分析/创意产生 ##

打开ipython

from IPython.display import IFrame
    IFrame(src="http://pandas.pydata.org", width=800, height=350)
    ----------
    <IPython.lib.display.IFrame at 0x222d1e0dc50>

import datetime
    import pandas as pd
    import pandas_datareader
    from pandas import Series, DataFrame
    print(pd.__version__)
    ----------
    0.25.1

import matplotlib.pyplot as plt
    import matplotlib as mpl
    mpl.rc('figure', figsize=(8, 7))
    mpl.__version__
    ----------
    3.0.2

## 创建/加载时间序列数据 ##

*  Python结构
 *  雅虎财经
 *  CSV文件

### Python结构 ###

labels = ['a', 'b', 'c', 'd', 'e']
    s = Series([1, 2, 3, 4, 5], index=labels)
    s
    ----------
    a    1
    b    2
    c    3
    d    4
    e    5
    dtype: int64

'b' in s
    ----------
    True

s['b']
    ----------
    2

mapping = s.to_dict()
    mapping
    ----------
    {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}

Series(mapping)
    ----------
    a    1
    b    2
    c    3
    d    4
    e    5
    dtype: int64

### 雅虎财经 ###

import pandas_datareader as pd_data
    import datetime
    aapl = pd_data.data.get_data_yahoo('AAPL',
                                       start=datetime.datetime(2006, 10, 1),
                                       end=datetime.datetime(2012, 1, 1))
    aapl.head()
    ----------
                     High        Low       Open      Close     Volume  Adj Close
    Date                                                                        
    2006-10-02  10.838572  10.614285  10.728572  10.694285  178159800   9.283074
    2006-10-03  10.707143  10.455714  10.635715  10.582857  197677200   9.186352
    2006-10-04  10.780000  10.451428  10.585714  10.768572  207270700   9.347562
    2006-10-05  10.880000  10.590000  10.647142  10.690000  170970800   9.279355
    2006-10-06  10.720000  10.544286  10.631429  10.602858  116739700   9.203714

### CSV文件 ###

> 需要在当前目录下创建这个文件 `data/aapl_ohlc.csv`

Date,Open,High,Low,Close,Volume,Adj Close
    2006-10-02,75.1,75.87,74.3,74.86,25451400,73.29
    2006-10-03,74.45,74.95,73.19,74.08,28239600,72.52
    2006-10-04,74.1,75.46,73.16,75.38,29610100,73.8
    2006-10-05,74.53,76.16,74.13,74.83,24424400,73.26
    2006-10-06,74.42,75.04,73.81,74.22,16677100,72.66
    2006-10-09,73.8,75.08,73.53,74.63,15650800,73.06
    2006-10-10,74.54,74.58,73.08,73.81,18985300,72.26
    2006-10-11,73.42,73.98,72.6,73.23,20423400,71.69
    2006-10-12,73.61,75.39,73.6,75.26,21173400,73.68

aapl.to_csv('data/aapl_ohlc.csv')
    !head data/aapl_ohlc.csv
    
    df = pd.read_csv('data/aapl_ohlc.csv', index_col='Date', parse_dates=True)
    df.head()
    ----------
                     High        Low       Open      Close     Volume  Adj Close
    Date                                                                        
    2006-10-02  10.838572  10.614285  10.728572  10.694285  178159800   9.283074
    2006-10-03  10.707143  10.455714  10.635715  10.582857  197677200   9.186352
    2006-10-04  10.780000  10.451428  10.585714  10.768572  207270700   9.347562
    2006-10-05  10.880000  10.590000  10.647142  10.690000  170970800   9.279355
    2006-10-06  10.720000  10.544286  10.631429  10.602858  116739700   9.203714

df.index
    ----------
    DatetimeIndex(['2006-10-02', '2006-10-03', '2006-10-04', '2006-10-05',
                   '2006-10-06', '2006-10-09', '2006-10-10', '2006-10-11',
                   '2006-10-12', '2006-10-13',
                   ...
                   '2011-12-16', '2011-12-19', '2011-12-20', '2011-12-21',
                   '2011-12-22', '2011-12-23', '2011-12-27', '2011-12-28',
                   '2011-12-29', '2011-12-30'],
                  dtype='datetime64[ns]', name='Date', length=1323, freq=None)

### data.io的更换 ###

原文中使用的 `pandas.io.data` 已经被弃用了，目前需要重新安装，本文中的使用方法为： `import pandas_datareader as pd_data`

官网：https://pandas-datareader.readthedocs.io/en/latest/  
安装地址：https://pypi.org/project/pandas-datareader/

*  v0.8.0 是支持 Python 2.7 的最后一个版本，所以务必安装 v0.8.1 及以上版本.

## Series 和 DataFrame ：第一步 ##

*  索引
 *  切片
 *  创建新列

ts = df['Close'][-10:]
    ts
    ----------
    Date
    2011-12-16    54.431427
    2011-12-19    54.601429
    2011-12-20    56.564285
    2011-12-21    56.635715
    2011-12-22    56.935715
    2011-12-23    57.618572
    2011-12-27    58.075714
    2011-12-28    57.520000
    2011-12-29    57.874287
    2011-12-30    57.857143
    Name: Close, dtype: float64

**DataFrame是一系列对象的集合。将DataFrame列切割出来将返回一个系列。**

type(ts)
    ----------
    pandas.core.series.Series

date = ts.index[5]
    date
    ----------
    Timestamp('2011-12-23 00:00:00')

ts[date]
    ----------
    57.61857223510742

ts[5]
    ----------
    57.61857223510742

我们还可以选择多列。

df[['Open', 'Close']].head()
    ----------
                     Open      Close
    Date                            
    2006-10-02  10.728572  10.694285
    2006-10-03  10.635715  10.582857
    2006-10-04  10.585714  10.768572
    2006-10-05  10.647142  10.690000
    2006-10-06  10.631429  10.602858

还可以动态添加新列

df['diff'] = df.Open - df.Close
    df.head()
    ----------
                     High        Low       Open  ...     Volume  Adj Close      diff
    Date                                         ...                                
    2006-10-02  10.838572  10.614285  10.728572  ...  178159800   9.283074  0.034286
    2006-10-03  10.707143  10.455714  10.635715  ...  197677200   9.186352  0.052857
    2006-10-04  10.780000  10.451428  10.585714  ...  207270700   9.347562 -0.182858
    2006-10-05  10.880000  10.590000  10.647142  ...  170970800   9.279355 -0.042857
    2006-10-06  10.720000  10.544286  10.631429  ...  116739700   9.203714  0.028571
    [5 rows x 7 columns]

也能动态删除

del df['diff']
    df.head()
    ----------
                     High        Low       Open      Close     Volume  Adj Close
    Date                                                                        
    2006-10-02  10.838572  10.614285  10.728572  10.694285  178159800   9.283074
    2006-10-03  10.707143  10.455714  10.635715  10.582857  197677200   9.186352
    2006-10-04  10.780000  10.451428  10.585714  10.768572  207270700   9.347562
    2006-10-05  10.880000  10.590000  10.647142  10.690000  170970800   9.279355
    2006-10-06  10.720000  10.544286  10.631429  10.602858  116739700   9.203714

## 常见的财务计算 ##

*  Moving Average 动态均线
 *  Returns 收益

close_px = df['Adj Close']
    
    mavg = close_px.rolling(40).mean()
    mavg[-10:]
    ----------
    Date
    2011-12-16    48.202029
    2011-12-19    48.168981
    2011-12-20    48.138538
    2011-12-21    48.134446
    2011-12-22    48.128090
    2011-12-23    48.123874
    2011-12-27    48.128772
    2011-12-28    48.122138

Returns 定义为:

r t = p t − p t − 1 p t − 1 = p t p t − 1 − 1 r\_t = \\frac\{p\_t - p\_\{t-1\}\}\{p\_\{t-1\}\} = \\frac\{p\_t\}\{p\_\{t-1\}\} - 1 rt=pt−1pt−pt−1=pt−1pt−1

rets = close_px / close_px.shift(1) - 1
    rets.head()
    ----------
    Date
    2006-10-02         NaN
    2006-10-03   -0.010419
    2006-10-04    0.017549
    2006-10-05   -0.007297
    2006-10-06   -0.008152
    Name: Adj Close, dtype: float64

或者用 `.pct_change()` ，得到的结果也是一样的

close_px.pct_change().head()
    ----------
    Date
    2006-10-02         NaN
    2006-10-03   -0.010419
    2006-10-04    0.017549
    2006-10-05   -0.007297
    2006-10-06   -0.008152
    Name: Adj Close, dtype: float64

## 绘图基础 ##

Series 和 DataFrames 有一个关联的 `.plot()` 命令 （ 在幕后使用Matplotlib ）

import matplotlib.pyplot as plt
    close_px.plot(label='AAPL')
    mavg.plot(label='mavg')
    plt.legend()
    ----------
    <matplotlib.legend.Legend at 0x182f3a8cac8>

`plt.show()`  
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## 可选：如果有时间的话… ##

import pandas as pd
    import pandas_datareader as pdd
    import datetime
    
    df = pdd.data.get_data_yahoo(['AAPL', 'GE', 'GOOG', 'IBM', 'KO', 'MSFT', 'PEP'],
                            start=datetime.datetime(2010, 1, 1),
                            end=datetime.datetime(2013, 1, 1))['Adj Close']
    df.head()
    ----------
    Symbols          AAPL         GE        GOOG  ...         KO       MSFT        PEP
    Date                                          ...                                 
    2009-12-31  26.131752  10.526512  308.832428  ...  19.278732  23.925440  44.622261
    2010-01-04  26.538483  10.749147  312.204773  ...  19.292267  24.294369  44.945187
    2010-01-05  26.584366  10.804806  310.829926  ...  19.058893  24.302216  45.488274
    2010-01-06  26.161509  10.749147  302.994293  ...  19.052124  24.153070  45.033253
    2010-01-07  26.113146  11.305734  295.940735  ...  19.004770  23.901886  44.747028
    [5 rows x 7 columns]

import matplotlib.pyplot as plt
    
    rets = df.pct_change()
    
    plt.scatter(rets.PEP, rets.KO)
    plt.xlabel('Returns PEP')
    plt.ylabel('Returns KO')
    ----------
    Text(0, 0.5, 'Returns KO')

`plt.show()`

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pandas的矩阵实际上要好一些，但我这里给出的是一个数组，如果要展示的话，还是用`plt.show()` 就行了

from pandas.plotting import scatter_matrix
    scatter_matrix(rets, diagonal='kde', figsize=(10, 10))
    ----------
    array([[<matplotlib.axes._subplots.AxesSubplot object at 0x000001E6FFEE55C0>,
            <matplotlib.axes._subplots.AxesSubplot object at 0x000001E6FFF3C7F0>,
    		...
            <matplotlib.axes._subplots.AxesSubplot object at 0x000001E6816D85F8>,
            <matplotlib.axes._subplots.AxesSubplot object at 0x000001E681701B70>]],
          dtype=object)

`plt.show()`

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corr = rets.corr()
    corr
    ----------
    Symbols      AAPL        GE      GOOG       IBM        KO      MSFT       PEP
    Symbols                                                                      
    AAPL     1.000000  0.457677  0.533692  0.502091  0.389567  0.473377  0.308979
    GE       0.457677  1.000000  0.463039  0.609821  0.594637  0.600791  0.534035
    GOOG     0.533692  0.463039  1.000000  0.471161  0.401712  0.473264  0.330564
    IBM      0.502091  0.609821  0.471161  1.000000  0.600568  0.646600  0.490903
    KO       0.389567  0.594637  0.401712  0.600568  1.000000  0.530160  0.635659
    MSFT     0.473377  0.600791  0.473264  0.646600  0.530160  1.000000  0.477452
    PEP      0.308979  0.534035  0.330564  0.490903  0.635659  0.477452  1.000000

plt.imshow(corr, cmap='hot', interpolation='none')
    plt.colorbar()
    plt.xticks(range(len(corr)), corr.columns)
    plt.yticks(range(len(corr)), corr.columns);
    plt.show()

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我们经常感兴趣的一件事是预期回报与我们承担的风险之间的关系。这两者之间往往存在一种取舍。这里用 `plt.annotate` 在散布图上做标记。

plt.scatter(rets.mean(), rets.std())
    plt.xlabel('Expected returns')
    plt.ylabel('Risk')
    for label, x, y in zip(rets.columns, rets.mean(), rets.std()):
        plt.annotate(
            label,
            xy=(x, y), xytext=(20, -20),
            textcoords='offset points', ha='right', va='bottom',
            bbox=dict(boxstyle='round,pad=0.5', fc='yellow', alpha=0.5),
            arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=0'))
    plt.show()
    ----------

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## 数据对齐和处理丢失的值 ##

*  Join, merge, concatenate
 *  填充 NaNs

让我们从雅虎财经获取更多的证券，并建立一个调整后的收盘价的 DataFrame。

series_list = []
    securities = ['AAPL', 'GOOG', 'IBM', 'MSFT']
    for security in securities:
        s = pd.io.data.get_data_yahoo(security, start=datetime.datetime(2011, 10, 1), end=datetime.datetime(2013, 1, 1))['Adj Close']
        s.name = security # Rename series to match security name
        series_list.append(s)

`pd.concat` 可以把多个 `Series` 连接到一个 `DataFrame` 中。

df = pd.concat(series_list, axis=1)
    df.head()
    ----------
                     AAPL        GOOG         IBM       MSFT
    Date                                                    
    2011-09-30  47.285904  256.558350  130.822800  20.321293
    2011-10-03  46.452591  246.834808  129.640747  20.027370
    2011-10-04  46.192177  250.012894  130.725555  20.688694
    2011-10-05  46.905209  251.407669  132.304108  21.137737
    2011-10-06  46.796078  256.393982  135.924973  21.505136

import numpy as np
    df.ix[0, 'AAPL'] = np.nan
    df.ix[1, ['GOOG', 'IBM']] = np.nan
    df.ix[[1, 2, 3], 'MSFT'] = np.nan
    df.head()
    ----------
                     AAPL        GOOG         IBM       MSFT
    Date                                                    
    2011-09-30        NaN  256.558350  130.822800  20.321293
    2011-10-03  46.452591         NaN         NaN        NaN
    2011-10-04  46.192177  250.012894  130.725555        NaN
    2011-10-05  46.905209  251.407669  132.304108        NaN
    2011-10-06  46.796078  256.393982  135.924973  21.505136

panda对缺少值的计算提供了强大的支持。

(df.AAPL + df.GOOG).head()
    ----------
    Date
    2011-09-30           NaN
    2011-10-03           NaN
    2011-10-04    296.205070
    2011-10-05    298.312878
    2011-10-06    303.190060
    dtype: float64

一种常用的时间序列缺失值的估算方法是正向填充法。

df.ffill().head()
    ----------
                     AAPL        GOOG         IBM       MSFT
    Date                                                    
    2011-09-30        NaN  256.558350  130.822800  20.321293
    2011-10-03  46.452591  256.558350  130.822800  20.321293
    2011-10-04  46.192177  250.012894  130.725555  20.321293
    2011-10-05  46.905209  251.407669  132.304108  20.321293
    2011-10-06  46.796078  256.393982  135.924973  21.505136