从R中的mysql中选择数据(带有for循环(?)) [英] select data from mysql (with for loop(?)) in R

问题描述

我想要的是:

m1 <- dbGetQuery(mydb, "select out,in from table where value > 1")
m2 <- dbGetQuery(mydb, "select out,in from table where value > 1.1")
m3 <- dbGetQuery(mydb, "select out,in from table where value > 1.2")
m4 <- dbGetQuery(mydb, "select out,in from table where value > 1.3")
                                .
                                .
                                .
m101 <- dbGetQuery(mydb, "select out,in from table where value > 10")

然后

n1 <- degree(graph.data.frame(m)) 
n2 <- degree(graph.data.frame(m2)
            .
            .
            .

我想用apply函数简化这些代码，但我不知道:^(

I would like to simplify these codes with apply function but I have no clue :^(

推荐答案

这是一个for循环解决方案，可将结果保存在列表中:

Here is a for loop solution that saves the results in a list:

# get list
myList <- list()

for(i in seq(1, 10, 0.1)) {
  myList[[paste0("m",i)]]<- dbGetQuery(mydb, 
                               paste("select out,in from table where value >", i))
}

然后可以从列表中调用对象:

You can then call the objects out of you list:

n1 <- degree(graph.data.frame(myList[["m1"]]))

和上面一样，您可以将这些结果放在列表中.命名列表是存储和组织许多对象的好方法.

and as above, you can put these results in a list. Named lists are a great way to store and organize many objects.

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