perl语言中,如果在一个双引号字符串中,包含一个变量名,这个部分将会被 替换成该变量的值。
这叫做变量内插。
1、一个例子:
$name = kino;
print "My name is $name"; #执行结果是"My name is kino"
2、变量内插只对双引号字符串有效,对单引号字符串是无效的。
print 'My name is $name';#$name并无特殊意义
3、如果双引号字符串中有一个未定义的变量,将以空值替换
print "Your name is $yourname"#执行结果是"Your name is "
4、识别变量名时,将取那个字符串中最长的有意义的那个:
$what = "people";
print "There are many $whats" #它将$whats作为变量名,而我们没定义这个变量,所以执行结果是"There are many "。这显然不是我们想要的结果
5、可以用{}明确指定变量名:
$what = "people";
print "There are many ${what}s"#执行结果"There are many peoples",这就是我们想要的结果
6、当我们想输入$时,而不是作为变量名的一部分,可以用转义:
print "There are many $whats" #结果就是"There are many $whats"