如何从数据框的单元格中获取值？ [英] How to get a value from a cell of a data frame?

问题描述

我已经构建了一个从数据框中提取出一行的条件：

I have constructed a condition that extract exactly one row from my data frame:

d2 = df[(df['l_ext']==l_ext) & (df['item']==item) & (df['wn']==wn) & (df['wd']==1)]

现在我想从一个特定的列：

Now I would like to take a value from a particular column:

val = d2['col_name']

但是，我得到一个包含一行和一列（ ie 一个单元格）的数据框。这不是我需要的我需要一个值（一个浮点数）。如何在大熊猫中做到这一点？

But as a result I get a data frame that contains one row and one column (i.e. one cell). It is not what I need. I need one value (one float number). How can I do it in pandas?

推荐答案

如果您只有一行的DataFrame，则访问第一个（仅）作为使用 iloc 的系列，然后使用列名称的值：

If you have a DataFrame with only one row, then access the first (only) row as a Series using iloc, and then the value using the column name:

In [3]: sub_df
Out[3]:
          A         B
2 -0.133653 -0.030854

In [4]: sub_df.iloc[0]
Out[4]:
A   -0.133653
B   -0.030854
Name: 2, dtype: float64

In [5]: sub_df.iloc[0]['A']
Out[5]: -0.13365288513107493

这篇关于如何从数据框的单元格中获取值？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！