perl initialize hash

I. Data Types(Data type): Perl has four data types: Scalar (variable), Scalar Array (Array), Hash Array (Hash), and References (pointer ), it seems to be rare, but it is more than enough to use it. Especially when writing Perl programs, you do not

Basic usage # initialize % H as an empty array % H ={}; # use an array to initialize % H as a => 1, B => 2% H = ('A', 1, 'B', 2); % H = ('A' => 1, 'B' => 2); # If the key is a string, % H = (a => 1, B => 2) can be omitted. # Use {} to access print "$

Chapter 2: References References are declared as scalar types (named variables starting with $), and reference is obtained using the \ operator. Modifying the referenced variable is equivalent to modifying the reference pointing to the

I. Introduction of the ModuleModule is the Perl package. The Perl object is based on a reference to the data item in the package.When you use object-oriented programming in other languages, you declare a class and then create an object (instance) of

1. Perl array (1): 1) initialize the array @ array = ("stringa", "stringb", "stringc "); 2) Print $ array [-1]; # output the stringc with the index (-1 + 3) % 3 = 2 3) dynamic growth $ array [4] = "stringd"; # Although $ array [3] is not used

1. Perl array (1 ): 1) initialize the array @ array = ("stringA", "stringB", "stringC ");2) print $ array [-1]; # output the stringC with the index (-1 + 3) % 3 = 23) dynamic growth $ array [4] = "stringD"; # Although $ array [3] is not used yet, it

1.Perl Array (1): 1 Initialize the array @array = ("Stringa", "StringB", "STRINGC");(2) using negative index loop to retrieve print $array [-1]; #输出索引为 (-1 + 3)% 3 = 2 STRINGC3 Dynamic growth $array [4] = "STRINGD"; #虽然 $array [3] has not yet been

There are five variables in Perl: Scalar, pointer, array, hash and handle. 1. scalar Let's take a look at scalar. scalar is the simplest data type in Perl. Variables of this data type can be numbers, strings, floating-point numbers, and are not

Chapter 2: List and array list (): Empty list, false when used as a condition judgment Two non-empty list examples: ("hello", "world", "\ n") (123,456,789) Different types of elements can be contained in the same list. The list in Perl is only

Array and hash table Ruby arrays and hash tables are index sets. Both objects are saved and can be read by keys. The key of the array is a number, but the hash table supports the object as the key. They all grow with the addition of new elements.