perl如何判断一个字符串的编码类型
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解决时间 2021-01-03 08:51
- 提问者网友：世勋超人
- 2021-01-03 05:58
perl如何判断一个字符串的编码类型
最佳答案
- 五星知识达人网友：佘樂
- 2021-01-10 05:36
perldoc -f ref
ref EXPR
ref Returns a non-empty string if EXPR is a reference, the empty string otherwise. If EXPR is not specified, $_ will be used. The value
returned depends on the type of thing the reference is a reference to. Builtin types include:
SCALAR
ARRAY
HASH
CODE
REF
GLOB
LVALUE
If the referenced object has been blessed into a package, then that package name is returned instead. You can think of "ref" as a
"typeof" operator.
if (ref($r) eq "HASH") {
print "r is a reference to a hash.\n";
}
unless (ref($r)) {
print "r is not a reference at all.\n";
}
if (UNIVERSAL::isa($r, "HASH")) { # for subclassing
print "r is a reference to something that isa hash.\n";
}
See also perlref.
ref EXPR
ref Returns a non-empty string if EXPR is a reference, the empty string otherwise. If EXPR is not specified, $_ will be used. The value
returned depends on the type of thing the reference is a reference to. Builtin types include:
SCALAR
ARRAY
HASH
CODE
REF
GLOB
LVALUE
If the referenced object has been blessed into a package, then that package name is returned instead. You can think of "ref" as a
"typeof" operator.
if (ref($r) eq "HASH") {
print "r is a reference to a hash.\n";
}
unless (ref($r)) {
print "r is not a reference at all.\n";
}
if (UNIVERSAL::isa($r, "HASH")) { # for subclassing
print "r is a reference to something that isa hash.\n";
}
See also perlref.
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