Added three example changes in NEWS.Rd

doc/NEWS.Rd

@@ -23,6 +23,10 @@
 
       \item \code{confint.default()} now also works on S4 objects, as long as
       suitable \code{coef()} and \code{vcov()} methods exist.
+      \preformatted{
+      obj <- new("MyS4Class")
+      confint(obj)
+      }
 
       \item \code{binomial(identity)} and \code{quasibinomial(identity)} now work
       without having to quote the argument.
@@ -48,6 +52,10 @@
       \samp{R >= 4.6.0}.
 
       \item \code{tools::analyze_license()} now also computes
+      \abbr{SPDX} license identifiers. Example usage:
+      \preformatted{
+      tools::analyze_license("DESCRIPTION")
+      }
       \href{https://spdx.dev/learn/handling-license-info/}{\abbr{SPDX}
 	license identifiers},
       thanks to \I{Thierry Onkelinx} and \I{LLuís Revilla}.
@@ -126,10 +134,12 @@
       to allow literal pattern matching.  Suggested and implemented
       by \I{Duncan Murdoch} in \PR{18925}.
 
-      \item \code{substring(txt, i1, i2)}, \code{substr(..)} and their
-      replacement versions now accept \code{i2 = NULL} to mean \dQuote{to
-      the end_of_string}, thus fulfilling \I{Kevin Ushey} (and others')
-      suggestions in \PR{18851}.
+      \item \code{substring(txt, i1, i2)} now accepts \code{i2 = NULL} 
+      to mean "to the end of string". Example:
+      \preformatted{
+      substring("Hello World", 7)      # returns "World"
+      substring("Hello World", 7, NULL) # same result
+      }
 
       \item The default method for \code{pretty()} gets a new switch \code{bounds} for
       completeness, corresponding to \code{.pretty()}.  Also, it now
@@ -6679,5 +6689,5 @@
     \ifelse{html}{\url{NEWS.3.html}}{\file{doc/html/NEWS.3.html}}
     and
     \ifelse{html}{\url{NEWS.2.html}}{\file{doc/html/NEWS.2.html}}.
-  }
+  } 
 }

src/library/base/man/paste.Rd

@@ -21,9 +21,10 @@ paste0(\dots,            collapse = NULL, recycle0 = FALSE)
     the result is always a string (\code{\link{character}} of length 1).}
   \item{recycle0}{\code{\link{logical}} indicating if zero-length
     character arguments should result in the zero-length
-    \code{\link{character}(0)}.  Note that when \code{collapse} is
+    \code{\link{character}(0)}. Note that when \code{collapse} is
     a string, \code{recycle0} does \emph{not} recycle to zero-length, but
-    to \code{""}.}% <== basic semantic of {collapse} mentioned above
+    to \code{""}.  This ensures that a single character string is always
+    returned when \code{collapse} is specified.}% <== basic semantic of {collapse} mentioned above
 }
 \description{
   Concatenate vectors after converting to character.
@@ -46,7 +47,8 @@ paste0(\dots,            collapse = NULL, recycle0 = FALSE)
   desirable, e.g.\sspace{}in \code{paste("the value of p is ", p)}.
 
   \code{paste0(\dots, collapse)} is equivalent to
-  \code{paste(\dots, sep = "", collapse)}, slightly more efficiently.
+  \code{paste(\dots, sep = "", collapse)}, slightly more efficiently
+  as it avoids handling a separator.
 
   If a value is specified for \code{collapse}, the values in the result
   are then concatenated into a single string, with the elements being

src/library/base/man/substr.Rd

@@ -58,6 +58,9 @@ substring(text, first, last = NULL) <- value
   If an input element has declared \code{"bytes"} encoding (see
   \code{\link{Encoding}}), the subsetting is done in units of bytes not
   characters.
+  When \code{start} or \code{stop} results in a zero-length extraction, an empty string
+  \code{""} is returned. Recycling is done to match the length of the longest input
+  vector, ensuring consistent behavior for vectorized operations.
 }
 \value{
   For \code{substr}, a character vector of the same length and with the
@@ -111,5 +114,9 @@ substring(x, 2) <- c("..", "+++")
 substring(X, 2) <- c("..", "+++")
 X
 stopifnot(x == X, identical(aX, attributes(X)), nzchar(comment(X)))
+
+## Demonstrating zero-length extraction behavior
+substr(character(0), 1, 2)        # returns character(0)
+substring(c("abc", ""), 2)       # returns "bc" and ""
 }
 \keyword{character}