根据条件将值分配给另一列中的一列

Question

说我有一个这样的清单：

> desired <- c("10001", "10004")

还有一个示例数据框，如下所示：

> desired_sample_df <- data.frame(geo = rep("other", 30), zip = c(rep(10001:10010, 2), 10011:10020), cbsa = c(rep("NY", 20), rep("CA", 10)))
> desired_sample_df
     geo   zip cbsa
1  other 10001   NY
2  other 10002   NY
3  other 10003   NY
4  other 10004   NY
5  other 10005   NY
6  other 10006   NY
7  other 10007   NY
8  other 10008   NY
9  other 10009   NY
10 other 10010   NY
11 other 10001   NY
12 other 10002   NY
13 other 10003   NY
14 other 10004   NY
15 other 10005   NY
16 other 10006   NY
17 other 10007   NY
18 other 10008   NY
19 other 10009   NY
20 other 10010   NY
21 other 10011   CA
22 other 10012   CA
23 other 10013   CA
24 other 10014   CA
25 other 10015   CA
26 other 10016   CA
27 other 10017   CA
28 other 10018   CA
29 other 10019   CA
30 other 10020   CA

仅当zip的值在开始时保存的desired列表中时，我才想用zip的值覆盖geo列。

---

这是我尝试过的：

> desired_sample_df$geo[desired_sample_df$zip %in% desired] <- desired_sample_df$zip[which(desired_sample_df$zip %in% desired)]
Warning message:
In `[<-.factor`(`*tmp*`, desired_sample_df$zip %in% desired, value = c(NA,  :
  invalid factor level, NA generated


> desired_sample_df$geo[desired_sample_df$zip %in% desired] <- desired_sample_df$zip
Warning messages:
1: In `[<-.factor`(`*tmp*`, desired_sample_df$zip %in% desired, value = c(NA,  :
  invalid factor level, NA generated
2: In `[<-.factor`(`*tmp*`, desired_sample_df$zip %in% desired, value = c(NA,  :
  number of items to replace is not a multiple of replacement length

Answer 1

问题之一是数据帧中的字符串会自动成为因素。 尝试这个：

desired <- c("10001", "10004")
df <- data.frame(geo = rep("other", 30), zip = c(rep(10001:10010, 2), 10011:10020), cbsa = c(rep("NY", 20), rep("CA", 10)), stringsAsFactors=FALSE)

idx <- df$zip %in% desired

现在，您可以通过以下方式更改所需的元素

df[idx, ]$geo <- df[idx, ]$zip

Answer 2

像这样？

df$geo <- ifelse(df$zip %in% desired,df$zip,df$geo)

在这里我叫你的desired_sample_df ，只是df 。