小编W W*_*W W的帖子

与ggplot最简单的方法是什么？

我是否需要调用prop.table或者是否有更简单的方法？

可复制的例子:

x <- c("good", "good", "bad", "bad", "bad", "bad", "perfect", "perfect", "perfect")
y <- c("exercise1", "exercise2", "exercise3", "exercise1", "exercise2", "exercise3", "exercise1", "exercise2", "exercise3")
dt <- data.frame(x, y)

ggplot(dt, aes(x, fill = y)) + geom_bar()

我在mongodb Java教程中找到了有关如何从mongo集合中查询的信息，但是eq它们对我来说不起作用！您知道如何使用mongo和java过滤集合中的文档吗？

这是我的尝试：

package Database;

import org.bson.Document;

import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;

public class StackOverflow {

    public static void main(String[] args) {

        // insert something to mongo:
        final String URI = "mongodb://localhost:27017";
        final String DB = "StackOverflowQuestion";
        final String COLLECTION = "eqDoesntExcist";

        MongoClientURI connection = new MongoClientURI(URI);
        MongoClient mongo = new MongoClient(connection);
        MongoDatabase database = mongo.getDatabase(DB);
        MongoCollection<Document> collection =  database.getCollection(COLLECTION);

        Document doc = new Document("name", "Troy").append("height", 185);
        collection.insertOne(doc);

        doc = new …

为什么当字符串包含时该String::matches方法返回？false\n

public class AppMain2 {

    public static void main(String[] args) {

        String data1 = "\n  London";    
        System.out.println(data1.matches(".*London.*")); // false
    }    
}

我正在进行聚合:

iris$group <- sample(1:2, 150, T)
aggregate(Sepal.Length ~ Species + group , data = iris, FUN = function(x) c(m = mean(x), n = length(x)))

现在我想group用变量替换:variable = "group"和聚合应该如上所述:

iris$group <- sample(1:2, 150, T)    
variable = "group"
aggregate(Sepal.Length ~ Species + variable , data = iris, FUN = function(x) c(m = mean(x), n = length(x)))

但然后发生错误.我尝试过eval,它没有帮助.

如果参数negation为真,那么condition应该否定.有没有更方便的方式来写这个？

foo <- function (x, type, negation){
  if(type == 1){
    condition <- x > 1
    if(negation){
      condition <- !condition
    }
  }
  if(type == 2){
    condition <- x == 5
    if(negation){
      condition <- !condition
    }
  }
  x[condition]
}

编辑:示例:

x <- 1:10

foo(x, 1, T) # 1
foo(x, 1, F) # 2  3  4  5  6  7  8  9 10
foo(x, 2, T) # 1  2  3  4  6  7  8  9 10
foo(x, 2, F) # …