5.17. Perl switch statement

Grammar #

Use Switch; Switch (argument) {case1 {print "number 1"} case "a" {print "string
{case [1.. 10,42] {print "Number in list"}case ( @ array) {print "Number in array"}case/ w+/
{print "Regular matching pattern"}caseqr/ w+/{
Print "regular matching pattern"} case ( % hash) {print "hash"}
case ( &sub) {print "child process"} else {print "does not match the previous condition"}}

The following is switch rules for the statement:

• Any type of switch scalar parameter can be used in parentheses of the statement.

• In a switch there can be any number of case statement. Every one of them. case followed by a value to be compared and a colon.

• The scalar case after the statement will match the switch the scalar of the statement is compared to determine whether it is equal.

• When the variable being tested is equal to case Constant time in case The following statement will be executed until it is encountered break Statement.

• switch statement can have an optional else the statement is at the end, and the statement is in all case executed in the case of a mismatch.

• When matching case after that, it will be executed case statement block code, jump out after execution switch statement.

• When matching case later, if we need to continue with the next case statement, you need to add next statement.

Example #

#/ Usr/bin/perluse
Switch$ Var=10@ Array=(10,20,30);% Hash=('key1 '=>10,'key2'=>20); Switch ($var) {case10 {print "number
10 n "{case" a "{print" string
{case [1.. 10,42] {print "Number in list"} case ( @ array) {print "Number in array"} case
( % hash) {print "In hash"}else {print "No matching condition"}}

Execute the above program, and the output is as follows:

Number 10

Next let’s take a look at the use of next example:

Example #

#/ Usr/bin/perluse
Switch$ Var=10@ Array=(10,20,30);% Hash=('key1 '=>10,'key2'=>20); Switch ($var) {case10 {print "number
10 n "; next;} # Continue executing case" a "{print" string after matching
{case [1.. 10,42] {print "Number in list"} case ( @ array) {print "Number in array"} case
( % hash) {print "In hash"}else {print "No matching condition"}}

Execute the above program, and the output is as follows:

Number 10
Numbers in the list