R-创建带转义引号的字符串，并使用变量的输入

我需要创建具有确切内容的字符串，以便在API REST客户端中使用

body =
      "{
        \"epic\":      \"sweden\",
        \"direction\": \"BUY\"
}"

我已经在通过创建字符串而不调用变量来使用解决方案。我现在希望用变量的输入构建字符串

我需要一个不添加更多R包的解决方案。最好是以最低的复杂度为一个良好的概述。我希望避免长正则表达式（但是如果正则表达式是一个很好的推荐方法，我愿意考虑）。 在attemp-1和attemp-2中，我故意省略了花括号，以使问题及其代码最小化。不过，它们的方括号需要成为解决方案的一部分

迄今为止的尝试：

Attemp-1（使用粘贴解决）：

epic1        <- paste0("\"", "sweden")
direction1   <- paste0("BUY", "\"")
create.body1 <- c(epic1, "," ,direction1)

epic2        <- paste0("\"", "sweden")
direction2   <- paste0("BUY", "\"")
create.body2 <- noquote(c(epic2, "," ,direction2))

# Curly brackets.
curly.bracket.left <- "{"
curly.bracket.right <- "}"

# Epic build [key/pair]
epic_key   <- "\"epic\": "
epic_value <- "\"sweden\""
epic_pair  <- c(epic_key, epic_value)

# Direction build [key/pair]
direction_key   <- "\"direction\": "
direction_value <- "\"BUY\""
direction_pair  <- c(direction_key, direction_value)

# Construct body string.
build.body <- c(
                curly.bracket.left,
                epic_pair,
                direction_pair,
                curly.bracket.right
)

问题：每个提供的变量输入都有引号。此外，转义字符仅作为完整字符串的包装添加，而不是根据需要为每个键和值添加

Attemp-2（用[noQuote]去掉引号）：

epic1        <- paste0("\"", "sweden")
direction1   <- paste0("BUY", "\"")
create.body1 <- c(epic1, "," ,direction1)

epic2        <- paste0("\"", "sweden")
direction2   <- paste0("BUY", "\"")
create.body2 <- noquote(c(epic2, "," ,direction2))

# Curly brackets.
curly.bracket.left <- "{"
curly.bracket.right <- "}"

# Epic build [key/pair]
epic_key   <- "\"epic\": "
epic_value <- "\"sweden\""
epic_pair  <- c(epic_key, epic_value)

# Direction build [key/pair]
direction_key   <- "\"direction\": "
direction_value <- "\"BUY\""
direction_pair  <- c(direction_key, direction_value)

# Construct body string.
build.body <- c(
                curly.bracket.left,
                epic_pair,
                direction_pair,
                curly.bracket.right
)

问题：所需的转义字符反斜杠已消失

Attemp-3（在构建主体字符串之前预构建[键/值对]）：

epic1        <- paste0("\"", "sweden")
direction1   <- paste0("BUY", "\"")
create.body1 <- c(epic1, "," ,direction1)

epic2        <- paste0("\"", "sweden")
direction2   <- paste0("BUY", "\"")
create.body2 <- noquote(c(epic2, "," ,direction2))

# Curly brackets.
curly.bracket.left <- "{"
curly.bracket.right <- "}"

# Epic build [key/pair]
epic_key   <- "\"epic\": "
epic_value <- "\"sweden\""
epic_pair  <- c(epic_key, epic_value)

# Direction build [key/pair]
direction_key   <- "\"direction\": "
direction_value <- "\"BUY\""
direction_pair  <- c(direction_key, direction_value)

# Construct body string.
build.body <- c(
                curly.bracket.left,
                epic_pair,
                direction_pair,
                curly.bracket.right
)

---

问题：正文字符串中有太多的引号。所有[\“]都很好。

我从你的第三次尝试开始。结果看起来像你想要的。我基本上只是将c（）切换为paste（），并在模板中有空间的地方插入了一些空间。这就是你需要的吗

curly.bracket.left <- "{"
curly.bracket.right <- "}"

# Epic build [key/pair]
epic_key   <- "\"epic\": "
epic_value <- "  \"sweden\","
epic_pair  <- c(epic_key, epic_value)

# Direction build [key/pair]
direction_key   <- "\"direction\": "
direction_value <- "\"BUY\""
direction_pair  <- c(direction_key, direction_value)

# Construct body string.
build.body <- c(
  curly.bracket.left,
  epic_pair,
  direction_pair,
  curly.bracket.right
)

string <- paste(curly.bracket.left, epic_key, epic_value, direction_key, direction_value, curly.bracket.right)

> print(string)
[1] "{ \"epic\":    \"sweden\", \"direction\":  \"BUY\" }" 

---

curly.bracket.left您是否尝试过粘贴（epic1，”，direction1，collapse=“”）

？它输出

“\”瑞典，购买\”“

@LAP:这几乎解决了问题。但是，您的建议将整个字符串包装在[\”]，同时主体需要以一种方式构建，即每个键和值都围绕[\”]也许在构建体字符串之前，我需要考虑对包含它的密钥和对的每个变量进行操作。