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.我想保留第一行作为数据，但是它一直在转换为列名.

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.

• 我尝试了header=False，但这只是将其完全删除了.

• I tried header=False but this just deleted it entirely.

(关于输入数据的注意:我有一个字符串(st = '\n'.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.)

(Note on my input data: I have a string (st = '\n'.join(lst)) that I convert to a file-like object (io.StringIO(st)), then build the csv from that file object.)

推荐答案

您希望header=None将False的类型提升为int到0中，请参见

You want header=None the False gets type promoted to int into 0 see the docs emphasis mine:

header:整数或整数列表，默认的推断"行号用作 列名以及数据的开头.默认行为就像 如果未传递任何名称，则设置为0，否则为无.显式传递标头= 0 才能替换现有名称.标头可以是以下内容的列表 指定列上多索引的行位置的整数 例如[0,1,3].未指定的中间行将被跳过 (例如，在此示例中为2).请注意，此参数将忽略 如果skip_blank_lines = True，则注释行和空行，因此header = 0 表示数据的第一行，而不是文件的第一行.

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.

首先可以通过header=0看到行为上的差异:

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

现在有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

请注意，在最新版本0.19.1中，这将引发一个TypeError:

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:将布尔值传递给标头无效.使用header = None表示否 标头或标头= int或类似列表的int以指定行 列名称

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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