Question

我需要编写一个搜索函数，以使用R在大型数据集中查找某些元素的开始和结束位置。

我的样本数据集如下：

C1   C2  Index
aa   J    1   
aa   J    2
aa   J    3
ab   O    4
aa   O    5
aa   J    6
aa   J    7
aa   J    8
aa   J    9
aa   K    10
ac   K    11
aa   J    12
aa   J    13

我想编写一个类似search("aa","J")的搜索功能（其中“ aa”是C1列中的值，而“ J”是C2列中的值）。该函数将首先根据“ aa”对数据集进行子集化；然后根据此子集提供索引。

结果将返回在如下矩阵中找到的所有位置的索引：

        [,1]   [,2]
[1,]     1      3
[2,]     5      8
[3,]     10     11

非常感谢您。

我试图修改提供的代码；但是有错误。您能帮忙看看吗？

get_inds <- function(test, C1, C2) {
   test <- subset(test, test$C1 == C1)
   inds <- rle(test$C1 == C1 & test$C2 == C2)
   end = cumsum(inds$lengths)
   start = c(1, head(end, -1) + 1)
   data.frame(start, end)[inds$values, ]
}

get_inds(test, 'aa', 'J')

Answer 1

@markus提供的链接可以解决您的问题，您需要根据需要进行修改。

[13:01:35] components/catalog/category/_landing.scss:455 [E] NestingDepth: Nesting should be no greater than 3, but was 4
[13:01:35] components/catalog/category/_landing.scss:495 [E] Indentation: Line should be indented 2 spaces, but was indented 4 spaces
[13:01:35] components/catalog/category/_layer.scss:46 [E] ColorVariable: Color literals like `#fff` should only be used in variable declarations; they should be referred to via variable everywhere else.
[13:01:35] components/catalog/product/_product-bikes.scss:41 [E] SelectorDepth: Selector should have depth of applicability no greater than 3, but was 4
[13:04:30] base/_dropdown.scss:80 [E] ImportantRule: !important should not be used

[13:04:30] components/account/_store-stock-checker.scss:69 [E] IdSelector: Avoid using id selectors
[13:04:30] vendor/font-awesome/_variables.scss:120 [E] StringQuotes: Prefer single quoted strings

您需要更改get_inds <- function(test, a, b) { test <- subset(test, C1 == a) inds <- rle(test$C1 == a & test$C2 == b) end = cumsum(inds$lengths) start = c(1, head(end, -1) + 1) df = data.frame(start, end)[inds$values, ] row.names(df) <- NULL df } get_inds(test, 'aa', 'J') # start end #1 1 3 #2 5 8 #3 10 11的条件，并删除不满足条件的行。

R搜索功能可返回开始和结束位置

1 个答案: