select()
R语言中的函数用于选择是否选择 DataFrame 的列。
用法: select(x, expr)
参数:
x: DataFrame
expr:选择条件
范例1:
# R program to select specific columns
# Loading library
library(dplyr)
# Create a data frame
d <- data.frame( name = c("Abhi", "Bhavesh", "Chaman", "Dimri"),
age = c(7, 5, 9, 16),
ht = c(46, NA, NA, 69),
school = c("yes", "yes", "no", "no") )
# startswith() function to print only ht data
select(d, starts_with("ht"))
# -startswith() function to
# print everything except ht data
select(d, -starts_with("ht"))
输出:
ht 1 46 2 NA 3 NA 4 69 name age school 1 Abhi 7 yes 2 Bhavesh 5 yes 3 Chaman 9 no 4 Dimri 16 no
范例2:
# R program to select specific columns
# Loading library
library(dplyr)
# Create a data frame
d <- data.frame( name = c("Abhi", "Bhavesh", "Chaman", "Dimri"),
age = c(7, 5, 9, 16),
ht = c(46, NA, NA, 69),
school = c("yes", "yes", "no", "no") )
# Printing column 1 to 2
select(d, 1:2)
# Printing data of column heading containing 'a'
select(d, contains("a"))
# Printing data of column heading which matches 'na'
select(d, matches("na"))
输出:
name age 1 Abhi 7 2 Bhavesh 5 3 Chaman 9 4 Dimri 16 name age 1 Abhi 7 2 Bhavesh 5 3 Chaman 9 4 Dimri 16 name 1 Abhi 2 Bhavesh 3 Chaman 4 Dimri
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注:本文由纯净天空筛选整理自nidhi_biet大神的英文原创作品 Choose Specific Columns of a Data Frame in R Programming – select() Function。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。