Pandas:如何根据另一列的值创建一列? [英] Pandas: How to create a column based on values of another column?

问题描述

我需要在数据框的末尾创建一个新列，其中该新列中的值是应用某些参数基于其他列的函数的结果.具体来说，来自另一列，但不同的行.例如，如果我的数据框有两列，分别包含值 x_i, y_i，我的第三列将是 f(x_(i-1),y_(i-1))

I need to create a new column at the end of a data frame, where the values in that new column are the result of applying some function who's parameters are based on other columns. Specifically, from another column, but a different row. So for example, if my data frame had two columns, containing values x_i, y_i respectively, my third column would be f(x_(i-1), y_(i-1))

我知道要创建一个新列，最简单的方法是执行类似

I know that to create create a new column, the easiest way would be to do something like

df['new_row'] = ...

但我不确定我可以设置什么.

But I'm not sure what I can set to that.

我该怎么做?

推荐答案

1   3
3   3
43  4
2   3

with open("file", 'r') as f:
     for line in f:
        n, r = line.split()
        formula = pow(int(n),int(r))
        print("{:4}{:4}{:9}".format(n,r, formula))

输出

1    3           1

3    3          27

43  4     3418801

2   3           8

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