在C ++代码中我找到了一行
SELECT
*
FROM post AS a
WHERE
a.lang = "fr"
OR (
a.lang = "en"
AND (
SELECT COUNT(*)
FROM post AS b
WHERE
b.lang = "fr"
AND b.postid = a.postid
) = 0
)
GROUP BY a.postid
在Visual Studio 12上越过此行时，std::string fruit = "" / "apple";变量最终包含 apple 。
但是 fruit的此运算符是什么意思？/
答案 0 :(得分：1)
C ++标准库没有为mydist <- dist(DATABASE)
clusters <- cutree(hclust(mydist), k = 3)
## Col means in each cluster
apply(DATABASE, 2, function (x) tapply(x, clusters, mean))
## or
DATABASE$cluster <- clusters # add cluster to DATABASE
# Now take means per group
library(dplyr)
centroids <- DATABASE %>%
group_by(cluster) %>%
summarise_all(funs(mean))
## Distance between centroids
dist(centroids[, -1], method = "euclidean")
## Example for distance in cluster 1 (distance between all observations of cluster 1)
DATABASE %>%
filter(cluster == 1) %>%
select(-cluster) %>%
dist()
或string定义除法运算符。所以这个code won't compile by itself
您可能在代码的其他地方有一个重载，该重载需要两个字符串或两个const char[N]，而实际上确实将其两个操作数连接在一起，即
const char[]