在 R 编程中寻找字符串中模式的匹配项 – pmatch()函数

R 语言中的pmatch()函数用于寻找作为参数传递的模式的匹配。它返回以正在搜索的模式开头的字符串。

Syntax: pmatch(pat, string, nomatch)

Parameters:
pat: pattern vector to be searched
string: vector to be matched
nomatch: return when no match is found

示例 1：

# R Program to match pattern in a string
  
# Creating string vector
x <- c("Geeks", "Books", "geek")
x
  
# Matching pattern
pmatch("gee", x) 
pmatch("Boo", x)

输出：

[1] "Geeks" "Books" "geek" 
[1] 3
[1] 2

示例 2：

# R Program to match pattern in a string
  
# Creating string vector
x <- c("Geeks", "Books", "geek")
x
  
# Matching pattern
pmatch(c("Gee", "Boo", "re"), x, nomatch = -1) 

输出：

[1] "Geeks" "Books" "geek" 
[1]  1  2 -1