在警告

Question

这似乎是一个简单的问题，但我找不到答案。我有一个包含调用参数名称的字符向量。在一个函数中，我想发出警告，如果其中一些是错误的，并引用名称。

bad = c("a", "b", "c")
warning(paste("Variables", paste(bad, collapse = ", "), "are wrong"))

给出：

Warning message:
Variables a, b, c are wrong 

但我需要：

Warning message:
Variables 'a', 'b', 'c' are wrong 

我想在不使用外部包的情况下实现这一目标。

Answer 1

我们可以使用ASCII撇号\'

warning(paste("Variables", paste0("\'", bad, "\'", collapse = ", "), "are wrong"))

# Warning message:
# Variables 'a', 'b', 'c' are wrong 

或sQuote

的单引号

warning(paste("Variables", paste(sQuote(bad), collapse = ", "), "are wrong"))

# Warning message:
# Variables ‘a’, ‘b’, ‘c’ are wrong 

或dQuote

的双引号

warning(paste("Variables", paste(dQuote(bad), collapse = ", "), "are wrong"))

# Warning message:
# Variables “a”, “b”, “c” are wrong

Answer 2

您可以使用此方法：

warning("Variables ", paste0("'", bad, "'", collapse = ", "), " are wrong")
# Warning message:
# Variables 'a', 'b', 'c' are wrong 

双引号的替代版本：

warning("Variables ", paste0("\"", bad, "\"", collapse = ", "), " are wrong")
# Warning message:
# Variables "a", "b", "c" are wrong 

Answer 3

这是你要找的吗？

bad = c("'a'", "'b'", "'c'")
warning(paste("Variables", paste(bad, collapse = ", "), "are wrong"))

如果您想保存一些打字，可以写一些类似

的内容

quotify <- function(x) paste0("'", x, "'")

bad = quotify(c("a", "b", "c"))
warning(paste("Variables", paste(bad, collapse = ", "), "are wrong"))