Perl 诊断消息 Not an ARRAY reference (F-致命错误-可捕获) Perl试图把一个引用解释成一个数组值,但是却发现引用丁其他的东西。你可以用ref函数看它究竟是什么类型的引用。
#push @{$vs1{'$key'}},14; #Not an ARRAY reference print@{${$vs1{'$key'}}};#sdwe 等同于 $vs1{'$key'} = ['sd','we'];print@{$vs1{'$key'}};#sdwe 也就是说开始的\是多余的,因为[]返回的已经是reference 这也是为什么 $vs1{'$key'} = \['sd','we'];print${$vs1{'$key'...
@array[0,1]=("string",46);#@array=("string",46,3,4,5)now @array[0..3]=(11,22,33,44);#@array=(11,22,33,44,5)now @array[1,2,3]=@array[3,2,4];#@array=(11,44,33,5,5)now @array[0..2]=@array[3,4];#@array=(5,5,"",5,5)now 可以用子Perl数组形式来交换元素...
/usr/bin/perl$age =25;# An integer assignment$name ="John Paul";# A string$salary =1445.50;# A floating pointprint"Age = $age\n";print"Name = $name\n";print"Salary = $salary\n";12345678 这将产生以下结果 - Age = 25 Name = John Paul Salary = 1445.5 1234 数字标量 标量通常是数...
# fetch all rows into a reference to an array of references my $matrix_ref = $dbh -> selectall_arrayref ($query); # determine dimensions of matrix my $rows = (!defined ($matrix_ref) ? 0 : scalar (@{$matrix_ref})); my $cols = ($rows == 0 ? 0 : scalar (@{$matrix_ref...
print "r is a reference to a hash./n"; } unless (ref($r)) { print "r is not a reference at all./n"; } 举例 简单来说,就是如果一个变量是个引用,那ref就可以返回一个表示其实际引用对象的描述性字符串,否则就会返回空值。如果没有指定ref函数的参数,默认对$_变量操作。如果被引用的对象已经...
If we passed the array to a subroutine, Perl copies the entire array into the @_ variable. When the array is big, this is not an effective method. When we want the original array to be modified by the subroutine, we need to pass the reference of the array. ...
sub AUTOLOAD { my $self = shift; my $type = ref ($self) || croak "$self is not an object"; my $field = $AUTOLOAD; $field =~ s/.*://; unless (exists $self->{$field}) { croak "$field does not exist in object/class $type"; } if (@_) { return $self->($name) = ...
Explanation: If we had an array reference in$arthen we would write@$arto dereference it. Because we have the array reference in$_[0]we could just put the@at the beginning:@$_[0], but then it would not be clear: Did we want to de-reference$_[0]; or did we want to de-reference...
Perl的变量有三种类型:标量(scalar),数组(array)和哈希(hash)。每种类型有它自己的记号,分别是￥,@和%。变量用my声明,保存到封闭的块(enclosing block)或者文件(file)的结尾。 标量变量 ·标量变量可以储存: ·undef(和Nonein Python,nullin PHP一致) ...