更新R中的列

我有一个数据帧：

df = data.frame(matrix(rnorm(5), nrow=5))

为此，我添加了一个离散变量

df$discrete <- c(0,1,0,1,0)

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df$discrete您正在尝试为数据帧列的子集（
df$new\u var[df$discrete==1]
）分配整个数据帧列中的数据（稍微更改）：
df$start+10

试试这个，它是双方的子集

df$new_var[df$discrete == 1]  <- df$start[df$discrete == 1] + 10

df$new\u var[df$discrete==1]
df$new_var <- as.numeric(10)

df$new_var[df$discrete == 1]  <- df$start + 10

df = data.frame(matrix(rnorm(5), nrow=5))
df$discrete <- c(0,1,0,1,0)
colnames (df) <- c("start", "discrete")
df$new_var <- as.numeric(10)
df$new_var[df$discrete == 1]  <- df$start + 10

df$new_var[df$discrete == 1]  <- df$start[df$discrete == 1] + 10