第十一课： - 合并来自各种来源的数据

第 11 课

从多个Excel文件中抓取数据并将它们合并到一个数据帧中。

In [1]:

import pandas as pd
import matplotlib
import os
import sys
%matplotlib inline

In [2]:

print('Python version ' + sys.version)
print('Pandas version ' + pd.__version__)
print('Matplotlib version ' + matplotlib.__version__) 

Python version 3.5.1 |Anaconda custom (64-bit)| (default, Feb 16 2016, 09:49:46) [MSC v.1900 64 bit (AMD64)]
Pandas version 0.20.1
Matplotlib version 1.5.1

 

创建3个excel文件

In [3]:

# Create DataFrame
d = {'Channel':[1], 'Number':[255]}
df = pd.DataFrame(d)
df

Out[3]:

	Channel	Number
0	1	255

In [4]:

# Export to Excel

df.to_excel('test1.xlsx', sheet_name = 'test1', index = False)
df.to_excel('test2.xlsx', sheet_name = 'test2', index = False)
df.to_excel('test3.xlsx', sheet_name = 'test3', index = False)
print('Done') 

Done 

将所有三个Excel文件放入一个DataFrame中 

获取文件名列表，确保文件夹中没有其他Excel文件。

In [5]:

# List to hold file names
FileNames = []

# Your path will be different, please modify the path below.
os.chdir(r"C:\Users\david\notebooks\update")

# Find any file that ends with ".xlsx"
for files in os.listdir("."):
    if files.endswith(".xlsx"):
        FileNames.append(files)
        
FileNames

Out[5]:

['test1.xlsx', 'test2.xlsx', 'test3.xlsx'] 

创建一个函数来处理所有的excel文件。

In [6]:

def GetFile(fnombre):

    # Path to excel file
    # Your path will be different, please modify the path below.
    location = r'C:\Users\david\notebooks\update\\' + fnombre
    
    # Parse the excel file
    # 0 = first sheet
    df = pd.read_excel(location, 0)
    
    # Tag record to file name
    df['File'] = fnombre
    
    # Make the "File" column the index of the df
    return df.set_index(['File'])

 遍历每个文件名，创建一个数据帧，并将其添加到列表中。

i.e.
df_list = [df, df, df]

In [7]:

# Create a list of dataframes
df_list = [GetFile(fname) for fname in FileNames]
df_list

Out[7]:

[            Channel  Number
 File                       
 test1.xlsx        1     255,             Channel  Number
 File                       
 test2.xlsx        1     255,             Channel  Number
 File                       
 test3.xlsx        1     255]

In [8]:

# Combine all of the dataframes into one
big_df = pd.concat(df_list)
big_df

Out[8]:

	Channel	Number
File
test1.xlsx	1	255
test2.xlsx	1	255
test3.xlsx	1	255

In [9]:

big_df.dtypes

Out[9]:

Channel    int64
Number     int64
dtype: object

In [10]:

# Plot it!
big_df['Channel'].plot.bar();

 

 

This tutorial was rewrited by CDS