防止 pandas read_csv 将第一行视为列名的标题 [英] Prevent pandas read_csv treating first row as header of column names
问题描述
我正在使用 pd.read_csv
读取 pandas DataFrame
.我想将第一行保留为数据,但它不断转换为列名.
- 我试过
header=False
但这只是完全删除了它.
(注意我的输入数据:我有一个字符串 (st = '
'.join(lst)
),我将其转换为类似文件的对象(io.StringIO(st)
),然后从该文件对象构建 csv
.)
你想要 header=None
把 False
类型提升为 int
进入 0
看到 文档强调我的:
header : int 或 int 列表,默认推断"行号用作列名和数据的开头.默认行为就像如果没有传递名称,则设置为 0,否则无.显式传递 header=0能够替换现有名称.标题可以是一个列表为列上的多索引指定行位置的整数例如[0,1,3].未指定的中间行将被跳过(例如,本例中的 2 被跳过).注意这个参数忽略如果skip_blank_lines=True,则注释行和空行,所以header=0表示数据的第一行而不是文件的第一行.
你可以看到行为的不同,首先是header=0
:
在 [95] 中:导入 io将熊猫导入为 pdt="""a,b,c0,1,23,4,5"""pd.read_csv(io.StringIO(t), header=0)出[95]:a b c0 0 1 21 3 4 5
现在使用 None
:
在[96]中:pd.read_csv(io.StringIO(t), header=None)出[96]:0 1 20 a b c1 0 1 22 3 4 5
请注意,在最新版本 0.19.1
中,这将引发 TypeError
:
在 [98] 中:pd.read_csv(io.StringIO(t), header=False)
<块引用>
TypeError: 将 bool 传递给 header 是无效的.使用 header=None 表示没有header 或 header=int 或类似整数的列表来指定行列名
I'm reading in a pandas DataFrame
using pd.read_csv
. I want to keep the first row as data, however it keeps getting converted to column names.
- I tried
header=False
but this just deleted it entirely.
(Note on my input data: I have a string (st = '
'.join(lst)
) that I convert to a file-like object (io.StringIO(st)
), then build the csv
from that file object.)
You want header=None
the False
gets type promoted to int
into 0
see the docs emphasis mine:
header : int or list of ints, default ‘infer’ Row number(s) to use as the column names, and the start of the data. Default behavior is as if set to 0 if no names passed, otherwise None. Explicitly pass header=0 to be able to replace existing names. The header can be a list of integers that specify row locations for a multi-index on the columns e.g. [0,1,3]. Intervening rows that are not specified will be skipped (e.g. 2 in this example is skipped). Note that this parameter ignores commented lines and empty lines if skip_blank_lines=True, so header=0 denotes the first line of data rather than the first line of the file.
You can see the difference in behaviour, first with header=0
:
In [95]:
import io
import pandas as pd
t="""a,b,c
0,1,2
3,4,5"""
pd.read_csv(io.StringIO(t), header=0)
Out[95]:
a b c
0 0 1 2
1 3 4 5
Now with None
:
In [96]:
pd.read_csv(io.StringIO(t), header=None)
Out[96]:
0 1 2
0 a b c
1 0 1 2
2 3 4 5
Note that in latest version 0.19.1
, this will now raise a TypeError
:
In [98]:
pd.read_csv(io.StringIO(t), header=False)
TypeError: Passing a bool to header is invalid. Use header=None for no header or header=int or list-like of ints to specify the row(s) making up the column names
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