Python:合并多个文本文件

时间:2014-10-07 19:10:30

标签: python csv pandas merge

我是Python的新手,而不是编程人员。我有40多个文本文件,我想要组合在一起(在'宽'csv中,而不是'高'csv。也就是说,我不想附加文件)并生成一个新的csv。

使用Pandas(合并)我能够实现我想要的,但我认为有一种更简单的方法。这是七个文件:


将pandas导入为pd

a = pd.read_csv("c:/pyTest/B01001.txt")
b = pd.read_csv("c:/pyTest/B01002.txt")
c = pd.read_csv("c:/pyTest/B01003.txt")
d = pd.read_csv("c:/pyTest/B02001.txt")
e = pd.read_csv("c:/pyTest/B05001.txt")
f = pd.read_csv("c:/pyTest/B05002.txt")
g = pd.read_csv("c:/pyTest/B05012.txt")

merged = a.merge(b.merge(c.merge(d.merge(e.merge(f.merge(g, on='GEOID'), on='GEOID'), on='GEOID'), on='GEOID'), on='GEOID'), on='GEOID')
merged.to_csv("c:/pytest/fook.csv", index=False)

如果重复的列名(例如'GEOID')也没有在输出文件中重复,那将会很棒。

您的任何帮助都非常感谢。

1 个答案:

答案 0 :(得分:2)

您可以将merge应用于DataFrames using reduce列表:

import pandas as pd
import functools

files = ["c:/pyTest/B01001.txt", "c:/pyTest/B01002.txt", "c:/pyTest/B01003.txt",
         "c:/pyTest/B02001.txt", "c:/pyTest/B05001.txt", "c:/pyTest/B05002.txt",
         "c:/pyTest/B05012.txt",]
dfs = [pd.read_csv(filename).set_index('GEOID') for filename in files]
mergefunc = functools.partial(pd.merge, left_index=True, right_index=True)
merged = functools.reduce(mergefunc, dfs)

merged.to_csv("c:/pytest/fook.csv", index=False)

当Pandas基于索引(而不是列)合并两个DataFrame时,生成的DataFrame使用合并索引。因此,您可以通过合并索引来避免重复GEOID列。


例如:

In [99]: import numpy as np
In [100]: import pandas as pd
In [101]: import functools

In [102]: dfs = [pd.DataFrame(np.arange(6).reshape(3,2), columns=['A','B{}'.format(i)]).set_index('A') for i in range(3)]

In [103]: mergefunc = functools.partial(pd.merge, left_index=True, right_index=True)    
In [104]: merged = functools.reduce(mergefunc, dfs)

In [105]: merged
Out[105]: 
   B0  B1  B2
A            
0   1   1   1
2   3   3   3
4   5   5   5