How do I force r to print character strings with single quotes?

Question

I'm writing some code that interfaces with SQL, and I need my character strings to print with single quotes, but R defaults to double quotes. When I go to ?Quotes, I don't see any guidance.

Any suggestions on how I can get the below character string to print as I'm typing it (with single quotes)?

help <- 'help me'
help

#Result :`-(
"help me"

Answer 1

Creating valid SQL statements programmatically is a common task in R. So, it is no surprise that there are already solutions available. Just to pick 2 Examples:

1. sqldf

This example is taken from G. Grothendiek's sqldf overview:

library(sqldf)
minSL <- 7
limit <- 3
species <- "virginica"
fn$sqldf("select * from iris where \"Sepal.Length\" > $minSL and species = '$species' limit $limit")

  Sepal.Length Sepal.Width Petal.Length Petal.Width   Species
1          7.1         3.0          5.9         2.1 virginica
2          7.6         3.0          6.6         2.1 virginica
3          7.3         2.9          6.3         1.8 virginica

2. glue

This example is modified from help("glue_sql", "glue"):

library(glue)
library(magrittr)
con <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
iris2 <- iris
colnames(iris2) <- gsub("[.]", "_", tolower(colnames(iris)))
DBI::dbWriteTable(con, "iris", iris2)
var <- "sepal_width"
tbl <- "iris"
num <- 2
val <- "setosa"
glue_sql("
  SELECT {`var`}
  FROM {`tbl`}
  WHERE {`tbl`}.sepal_length > {num}
    AND {`tbl`}.species = {val}
  LIMIT {limit}
  ", limit = 4, .con = con)  %T>%
  print()%>% 
  DBI::dbGetQuery(con, .)

<SQL> SELECT `sepal_width`
FROM `iris`
WHERE `iris`.sepal_length > 2
  AND `iris`.species = 'setosa'
LIMIT 4

  sepal_width
1         3.5
2         3.0
3         3.2
4         3.1

3. Other ressources

Perhaps, it might be worthwhile to study the help pages on SQL quoting (?DBI::SQL), or more low level: sprintf().