Question

这是一个简单的问题，难以在网上找到答案。情况如下：

>>> A
[('hey', 'you', 4), ('hey', 'not you', 5), ('not hey', 'you', 2), ('not hey', 'not you', 6)]
>>> A_p = pandas.DataFrame(A)
>>> A_p
         0        1  2
0      hey      you  4
1      hey  not you  5
2  not hey      you  2
3  not hey  not you  6
>>> B_p = A_p.pivot(0,1,2)
>>> B_p
1        not you  you
0                    
hey            5    4
not hey        6    2

这与pivot的文档中的建议不完全相同 - 在那里，它显示左上角没有1和0的结果。这就是我正在寻找的，一个打印为

的DataFrame对象

         not you  you
hey            5    4
not hey        6    2

问题是正常行为会导致第一行为

的csv文件

0,not you,you

当我真的想要

时

not you, you

当正常的csv文件（前面的“0”）读入R时，它没有正确地设置框架对象的列名和行名，导致手动操作痛苦以使其格式正确。有没有办法让枢轴给我一个DataFrame对象，而左上角没有附加信息？

Answer 1

嗯，你有：

In [17]: B_p.to_csv(sys.stdout)
0,not you,you
hey,5.0,4.0
not hey,6.0,2.0

In [18]: B_p.to_csv(sys.stdout, index=False)
not you,you
5.0,4.0
6.0,2.0

但我认为你想要行名称。将索引名称设置为None（B_p.index.name = None）会给出一个前导逗号：

In [20]: B_p.to_csv(sys.stdout)
,not you,you
hey,5.0,4.0
not hey,6.0,2.0

这大致匹配（忽略引用的字符串）当write.csv时R在row.names=TRUE中写入的内容：

"","a","b"
"foo",0.720538259472741,-0.848304940318957
"bar",-0.64266667412325,-0.442441171401282
"baz",-0.419181615269841,-0.658545964124229
"qux",0.881124313748992,0.36383198969179
"bar2",-1.35613767310069,-0.124014006180608

这些都有帮助吗？

编辑：今天添加了index_label=False选项，它可以满足您的需求：

In [2]: df
Out[2]: 
       A  B
one    1  4
two    2  5
three  3  6

In [3]: df.to_csv('foo.csv', index_
index_exp     index_label=  index_name=   

In [3]: df.to_csv('foo.csv', index_name=False)

In [4]: 
11:24 ~/code/pandas  (master)$ R

R version 2.14.0 (2011-10-31)
Copyright (C) 2011 The R Foundation for Statistical Computing
ISBN 3-900051-07-0
Platform: x86_64-unknown-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

  Natural language support but running in an English locale

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

[Previously saved workspace restored]

re> read.csv('foo.csv')
      A B
one   1 4
two   2 5
three 3 6

在Pandas中旋转DataFrame以输出到CSV

1 个答案: