'data.frame':3 obs. of 4 variables: $ ID : num 1 2 3 $ Name : Factor w/ 3 levels "Devin","Edward",..: 1 2 3 $ Gender : Factor w/ 2 levels "F","M": 2 2 1 $ Birthdate: Factor w/ 3 levels "1983-5-6","1984-12-29",..
对于我这种使用了多年SQL的人来说,如果能够直接写SQL语句对Data Frame进行查询操作,那是多么方便美妙的啊,结果还真有这么一个包:sqldf。 同样是前面的需求,对应的语句就是: library(sqldf) result<-sqldf("select Name,Age from student where Gender='F' and Age<30") 连接/合并 对于数据库来说,对多表进行...
使用data.frame函数就可以初始化一个Data Frame。比如我们要初始化一个student的Data Frame其中包含ID和Name还有Gender以及Birthdate,那么代码为: student<-data.frame(ID=c(11,12,13),Name=c("Devin","Edward","Wenli"),Gender=c("M","M","F"),Birthdate=c("1984-12-29","1983-5-6","1986-8-8...
zoo(data_ts) # convert to zoo ### INITILISATION X<-data_zoo #Rename variables (Norway_S = Southern Norway/ Norway_N = Northen Norway) colnames(X) <- c("Denmark","Finland", "Norway_S","Norway_N","Sweden") VARselect(X, type= "both", lag.max = 10) #VAR4 nlag = 4 nfore ...
函数用途select()选择变量/列filter()选择观测值/行mutate()转换或重编码变量,添加变量rename()重命名变量/列recode()重编码变量值arrange()按变量值对行进行排序(升序)desc()按变量值对行进行排序(倒序) leadership <- data.frame(manager=c(1,2,3,4,5), ...
使用SQL查询Data Frame 对于我这种使用了多年SQL的人来说,如果能够直接写SQL语句对Data Frame进行查询操作,那是多么方便美妙的啊,结果还真有这么一个包:sqldf。 同样是前面的需求,对应的语句就是: library(sqldf) result<-sqldf("select Name,Age from student where Gender='F' and Age<30") ...
使用SQL查询Data Frame 对于我这种使用了多年SQL的人来说,如果能够直接写SQL语句对Data Frame进行查询操作,那是多么方便美妙的啊,结果还真有这么一个包:sqldf。 同样是前面的需求,对应的语句就是: library(sqldf) result<-sqldf("select Name,Age from student where Gender='F' and Age<30") ...
Select Data Frame Rows based on Values in Vector Introduction to R Programming In summary: In this tutorial, I explained how toreturn only rows in a specific value rangein the R programming language. Don’t hesitate to let me know in the comments section, if you have any additional question...
Now, we can apply the fread command of the data.table package to read only selected variables by specifying the column names of the variables we want to import (i.e. select = c(“x1”, “x2”, “x4”)).data_import2 <- fread("C:/Users/Joach/Desktop/My Folder/data.csv", # ...
("Width"))# Select columns whose names contains "etal"my_data %>% select(contains("etal"))# Select columns whose name maches a regular expressionmy_data %>% select(matches(".t."))# selects variables provided in a character vector.my_data %>% select(one_of(c("Sepal.Length","Petal...