在整个数据帧中有条件地替换值

在不指定行或列的情况下,替换整个数据帧中的值的合适方法是什么?

abs(x) > .5 通过 <- "duck"

> df <- data.frame(a = rnorm(5), b = rnorm(5), c = rnorm(5))
> df
            a          b          c
1  1.37481216 -0.1760366 -0.5122730
2  0.09204844 -0.4270991  0.3211998
3 -0.43563818  0.7560178  0.5399643
4 -0.02078887  0.5961020 -0.5985515
5  0.99129234 -0.9959395 -0.6488177

期望的输出是

            a          b          c
1  "duck"     -0.1760366  "duck"
2  0.09204844 -0.4270991  0.3211998
3 -0.43563818  "duck"     "duck"
4 -0.02078887  "duck"     "duck"
5  "duck"      "duck"     "duck"

而 this post

谢谢