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Editor to share with you what Perl complex data structures are, I hope you will gain something after reading this article, let's discuss it together!

Perl complex data structure

Arrays and hashes are easy-to-use, simple, flat data structures, and unfortunately, reality is not what people want it to be. Many times you need to use difficult, complex, and non-planar data structures. Perl can make complicated things simple. The way to do this is to let you pretend that complex values are actually simple things. In other words, Perl allows you to manipulate simple scalars, which happen to be references to complex arrays and hashes. In natural language, we always use simple single nouns to represent complex and difficult entities, such as "government" to represent a complex shell and so on.

Continuing with the previous example, suppose we want to talk about Jacob's wife instead of Adam's, and Jacob has four wives (don't do it yourself). In order to represent this data structure in Perl, we would like to treat Jocob's four wives as one, but we will encounter some problems. You might think that we can use the following sentence to express:

$wife {"Jacob"} = ("Leah", "Rachel", 'Bilhah "," Zilpah "); # wrong

But this doesn't work the way you want it to, because brackets and commas are not strong enough in Perl to convert a list into scalars (in syntax, parentheses are used for grouping and commas are used for separation). You need to explicitly tell Perl that you want to treat a list as a scalar. Parentheses in [] can achieve this conversion:

$wife {"Jacob"} = ["Leah", "Rachel", "Bilhah", "Zilpah"]; # correct

This statement creates an unnamed array and places a reference to it in the hash element $wife {"Jacob"}. So we have a named hash that contains an unnamed array. This is how Perl handles multidimensional arrays and nested data types. Like normal arrays and hashes, you can assign them separately:

$wife {"Jacob"} [0] = "Leah"; $wife {"Jacob"} [1] = "Rachel"; $wife {"Jacob"} [2] = "Bilhah"; $wife {"Jacob"} [3] = "Zilpah"

As you can see above, this looks like a multi-dimensional array with a string subscript and a numeric subscript. To learn more about tree structures, such as nested data structures, suppose we want to list not only Jocob's wife, but also each wife's son, Perl complex data structure, in this case, we want to use the hash structure as a scalar. We can do this using curly brackets (in each hash value, an array is represented in brackets as in the previous example, and now we have an array in the hash).

$kids_of_wife {"Jacob"} = {

"Leah" = > ["Reuben", "Simeon", "Levi", "Judah", "Issachar", "Zebulun"]

"Rachel" = > ["Joseph", "Benjamin"]

"Bilhah" = > ["Dan", "Naphtali"]

"Zilpah" = > ["Gad", "Asher"],}

Similarly, we can say something like this:

$kids_of_wife {"Jacob"} {"Leah"} [0] = "Reuben"; $kids_of_wife {"Jacob"} {"Leah"} [1] = "Simeon"; $kids_of_wife {"Jacob"} {"Leah"} [2] = "Levi"; $kids_of_wife {"Jacob"} {"Leah"} [3] = "Judah"; $kids_of_wife {"Jacob"} {"Leah"} [4] = "Issachar" $kids_of_wife {"Jacob"} {"Leah"} [5] = "Zebulun"; $kids_of_wife {"Jacob"} {"Rachel"} [0] = "Joseph"; $kids_of_wife {"Jacob"} {"Rachel"} [1] = "Benjamin"; $kids_of_wife {"Jacob"} {"Bilhah"} [0] = "Dan"; $kids_of_wife {"Jacob"} {"Bilhah"} [1] = "Naphtali" $kids_of_wife {"Jacob"} {"Zilpah"} [0] = "Gad"; $kids_of_wife {"Jacob"} {"Zilpah"} [1] = "Asher"

As you can see above, adding a layer to a nested data structure is like adding a dimension to a multidimensional array. The representation is the same within Perl, but you can understand it in any way.

The most important point here is that Perl can represent Perl complex data structures with simple scalars. Perl uses this simple encapsulation method to build an object-based structure. When we call the constructor of the Camel object with the following method:

$fido=newCamel "Amelia"

We created a Camel object and represented it with a scalar $fido. But it is very complicated in the Camel object. As good object-oriented programmers, we don't want to care about the details of Camel objects (unless we are people who implement Camel class methods). In general, however, an object has a hash containing its properties in its composition. For example, its name (in this case, "Amelia" rather than "fido"), and the number of humps (we don't clearly define it here, so use the default value of 1, just like the cover).

After reading this article, I believe you have a certain understanding of "what are the complex data structures of Perl". If you want to know more about it, you are welcome to follow the industry information channel. Thank you for reading!

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