如何在数据框列上进行标量乘法 [英] How to do scalar multiply on data frame column
问题描述
我确定这个人正坐在我的面前,但我看不到它.我有一个数据框"a",例如:
I’m sure this one is sitting right in front of me but I can’t see it. I have a data frame, "a", such that:
>a
Chars Numbers
This A 15
That B 22
Other C 18
我只是想将Numbers列乘以标量,例如b< -10,并保持数据帧的其他部分不变.(我将在结果的Numbers列中得到150、220、180,但行/列标题和Chars列却相同.)
I simply want to multiply the Numbers column by a scalar, say b <- 10, and keep the other parts of the data frame intact. (I would get 150, 220, 180 in the Numbers column of the result, but the same row/column headings and Chars column.)
不起作用的是* b,尝试使用apply或a $ Numbers * b.
What does not work is a * b, trying to use apply, or a$Numbers * b.
推荐答案
尝试以下操作:
a$Numbers <- a$Numbers * b
为了解释正在发生的事情,让我们使用示例中的数字:
To explain what's happening, let's use the figures from your example:
上面的代码将允许您在 Numbers
列上使用标量乘法:
The above code will allow you to use scalar multiplication on the Numbers
column:
然后您将分配回 a
中的 Numbers
列:
Which you'll then assign back to the Numbers
column in a
:
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