Reordering the columns in a data frame

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Reordering the columns in a data frame

Problem You want to do reorder the columns in a data frame. Solution # A sample data frame data <- read.table(header=TRUE, text=' id weight size 1 20 small 2 27 large 3 24 medium ') # Reorder by column number data[c(1,3,2)] #> id size weight #> 1…

keep or remove data frame columns in R

You should use either indexing or the subset function. For example : R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8) R> df x y z u 1 1 2 3 4 2 2 3 4 5 3 3 4 5 6 4 4 5 6 7 5 5 6 7 8 Then you can use the which function and the - operator in column…

R语言 data.frame 大全

A data frame is used for storing data tables. It is a list of vectors of equal length. For example, the following variable df is a data frame containing three vectors n, s, b. > n = c(2, 3, 5) > s = c("aa", "bb", "cc") …

R class of subset of matrix and data.frame

a = matrix( c(2, 4, 3, 1, 5, 7), # the data elements nrow=2, # number of rows ncol=3, # number of columns byrow = TRUE) # fill matrix by rows class( (a[1,])[1] "numeric" class(a[c(1,2),])[1] &…

How do I extract a single column from a data.frame as a data.frame

Say I have a data.frame: df <- data.frame(A=c(10,20,30),B=c(11,22,33), C=c(111,222,333)) A B C1 10 11 1112 20 22 2223 30 33 333 If I select two (or more) columns I get a data.frame: x <- df[,1:2] A B 1 10 11 2 20 22 3 30 33 This is what I want…

R语言合并data.frame

Merging Data Adding Columns To merge two data frames (datasets) horizontally, use the merge function. In most cases, you join two data frames by one or more common key variables (i.e., an inner join). # merge two data frames by ID total <- merge(…

R vs Python：构建data.frame、读取csv与统计描述

一.Python 数据框就是典型的关系型数据库的数据存储形式,每一行是一条记录,每一列是一个属性,最终构成表格的形式,这是数据科学家必须熟悉的最典型的数据结构. 1.构建数据框 import pandas as pd data = {'year':[2010, 2011, 2012, 2010, 2011, 2012, 2010, 2011, 2012], 'team':['FCBarcelona', 'FCBarcelona', 'FCBarcelona', 'RMadrid', 'RMadr…