本文介绍了R用下一个非零值替换数据帧中的零的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个包含零值列的数据框:
I have a dataframe with a column containing zero values:
a <- 1:10 b <- c(1, 0, 0, 0, 0, -1, -1, 0, 0, 1) df <- data.frame(a, b) df如何将零值替换为最后一个非零值,即 df$b 列:
How can I replace the zero values with the last non zero value ie column df$b to be:
1,-1,-1,-1,-1,-1,-1,1,1,1感谢您的帮助.
推荐答案这是 zoo 的 na.locf 的一种方法.虽然这个方法在过程中确实把一些值改成了NA,但是代码很好,很轻松.
Here's one way with na.locf from zoo. Although this method does change some values to NA in the process, the code is nice and painless.
library(zoo) na.locf(with(df, ifelse(b == 0, NA_real_, b)), fromLast = TRUE) # [1] 1 -1 -1 -1 -1 -1 -1 1 1 1另一种替代方法,在长向量上可能比 ifelse 更快,是
An alternative to this, and one that might be faster than ifelse on long vectors, is
na.locf(with(df, { is.na(b) <- b == 0; b }), fromLast = TRUE) # [1] 1 -1 -1 -1 -1 -1 -1 1 1 1更多推荐
R用下一个非零值替换数据帧中的零
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