警告中引用名稱

Question

這似乎是一個簡單的問題，但我找不到答案。我有一個包含調用參數名稱的字符向量。在函數中，如果其中一些錯誤，我想提出警告，並引用名稱。

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

這給：

Warning message: 
Variables a, b, c are wrong 

，但我需要：

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

我想做到這一點，而無需使用外部包。

Answer 1

我們可以使用ASCII撇號他\'

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

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

或單引號由sQuote

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

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

或雙引號通過dQuote

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

# Warning message: 
# Variables 「a」, 「b」, 「c」 are wrong 

Answer 2

這是你在找什麼？

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

，如果你想節省一些打字，你可以寫類似

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

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

Answer 3

您可以使用此方法：

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

替代版本爲雙引號：

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