多个数据框列中的值合并成一个向量 [英] Values from multiple dataframe columns into one vector

问题描述

我有一个数据框 df ，其中有很多列，并说有100行.

I have a dataframe df that has many cols and say 100 rows.

如何从名称为"alpha"，"gamma"和"zeta"的列中获取所有级别值，并将其中的300个存储在单个向量中?

How do I take all the level values from the columns with names "alpha", "gamma" and "zeta" and store the 300 of them in a single vector?

推荐答案

我发现首先转换为矩阵可以更轻松地达到等级.

I've found that converting to a matrix first makes getting to levels a bit easier.

as.vector(as.matrix(df[,c("alpha", "gamma", "zeta")]))

当然，当您最初读取数据时，您可能只需完成 stringsAsFactors = FALSE .

Of course, you could have just done stringsAsFactors=FALSE when you read the data in initially.

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