R語言 char.expand()用法及代碼示例

R 語言中的 char.expand() 函數用於在其第二個元素中尋找其第一個參數的唯一匹配。如果成功，則返回該元素；否則，它將執行由第三個參數指定的操作。

用法： char.expand(input, target, nomatch = stop(“no match”))
參數： 
input: character string to be expanded 
target:character vector with the values to be matched against 
nomatch: an R expression to be evaluated in case expansion was not possible

範例1：

Python3


# R program to illustrate
# char.expand function
 
# Creating string vector
x <- c("sand", "and", "land")
 
# Calling char.expand() function
char.expand("a", x, warning("no expand"))
char.expand("an", x, warning("no expand"))
char.expand("and", x, warning("no expand"))

輸出：

[1] "and"
[1] "and"
[1] "and"

範例2：

Python3


# R program to illustrate
# char.expand function
 
# Creating string vector
x <- c("sand", "and", "land")
 
# Calling char.expand() function
char.expand("G", x, warning("no expand"))

輸出：

[1] NA
Warning message:
In eval(nomatch):no expand

相關用法

注：本文由純淨天空篩選整理自Kanchan_Ray大神的英文原創作品 Seeking a unique match of elements in R Programming – char.expand() Function。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。