True allergies to cow's milk are relatively uncommon. Only 2 to 3 percent of children are allergic to milk, according to the AAP, and almost all of them outgrow it by age 3. (Learn the difference between a milk allergy and lactose intolerance .).
The underscore [ _ ] (also called underline, underbar, low line, or low dash) is a character that originally appeared on the typewriter and was primarily used to underline words.
active oldest votes. up vote 52 down vote accepted. A word character is any letter or digit or the underscore character, that is, any character which can be part of a Perl word. The definition of letters and digits is controlled by PCRE's character tables, and may vary if locale-specific matching is taking place.