"Notice that the result of this query is a Factor array containing the database rows as arrays of strings. We would have to convert the " { $snippet "cover_price" } " from a string to a number in order to use it in a calculation." $nl
"In conclusion, this method of accessing a database is supported, but it is fairly low-level and generally specific to a single database. The " { $vocab-link "db.tuples" } " vocabulary is a good alternative to writing SQL by hand." ;
{ $description "Randomizes a sequence in-place with the Fisher-Yates algorithm and returns the sequence." } ;
+HELP: sample
+{ $values
+ { "seq" sequence } { "n" integer }
+ { "seq'" sequence }
+}
+{ $description "Takes " { $snippet "n" } " samples at random without replacement from a sequence. Throws an error if " { $snippet "n" } " is longer than the sequence." }
{ $values { "string" "literal and escaped characters" } }
-{ $description "Reads from the input string until the next occurrence of " { $link POSTPONE: " } " or " { $snippet "\"\"\"" } ", and appends the resulting string to the parse tree. String literals can span multiple lines. For strings beginning with a single double-quote, the " { $link POSTPONE: " } " character and various other special characters can be read by inserting " { $link "escape" } ". For triple quoted strings, the double-quote character does not require escaping." }
+{ $description "Reads from the input string until the next occurrence of " { $snippet "\"" } " or " { $snippet "\"\"\"" } ", and appends the resulting string to the parse tree. String literals can span multiple lines. Various special characters can be read by inserting " { $link "escape" } ". For triple quoted strings, the double-quote character does not require escaping." }