Difference Between Array and String

If anyone is even remotely familiar with the terms of computer programming, then there is a very good chance that one might have come across the terms Array and String.

Even if one does not know about programming, then also, one would have a fairly good idea about what these terms mean. This is because these terms are used quite a lot on a day to day basis.

When we talk about arrays, we think about a group of items kept together in an orderly fashion, such as an array of dominos. Again, when we talk about string, we think about a number of letters or a number of words.

When we say ‘That person spoke a string of words which made no sense’, we mean that the person spoke a collection of words that were arranged in a specific manner.

The above definitions might seem informal, however, the actual definitions of arrays and strings are not too different from these. 

Key Takeaways

1. An array is a collection of elements of the same data type, whereas a string is a collection of characters.
2. Arrays are mutable, meaning their values can be changed, whereas strings are immutable and cannot be changed once created.
3. Arrays are usually used for mathematical operations and storing and accessing large amounts of data, while strings represent text and manipulate strings.

Array vs String

The difference between array and string is that an array is a data structure capable of holding variables of any data type, while a string is an object that can only deal with the char data type.

Comparison Table

Parameters of Comparison	Array	String
Data Type	Arrays can hold items of any data type.	Strings can hold items of only the char data type.
Category	The array is a data structure.	The string is an object.
Mutability	Arrays are mutable.	Strings are immutable.
Length	The length of an array is fixed, whether by the programmer or the user when performing the operation.	The length of a string is not fixed.
End Character	Usually, arrays do not end with a null character.	Strings end with a null character.

What are Arrays?

An array is one of the most basic types of data structures that are present in programming. An array is a very fundamental unit in programming and is present in a lot of programs in order to deal with variables and process them, usually in an iterative manner.

However, the most important use for arrays usually is calculation purposes. Numerical values are entered one after the other, and then these values might get processed by one or more than one function, based on the program, which finally returns a zero, one, or more than one value in return.

Data structures are the skeleton structure that tells us how a group of data is inserted, and exactly how will the operations in a function deal with these data items. A few other important examples of data items are stacks, queues, linked lists, trees, etc.

What is important to know is that one can treat these data structures as secondary data structures, as all of them can be created with the help of arrays only. 

Another important characteristic of arrays that one should know is that the size of arrays is pre-defined by the programmer or by the user before the array is actually used. This is because arrays follow a method of iterative calculation.

That is a counter moves through each object in an array to seek a certain object. If the upper limit of the array is not known, then the counter does not know where to start or where to stop, which renders the array useless. Hence, it is important to specify the size of the array before using it.

Arrays need not be used only for calculation and can store any other data type other than numerical integer values too. Arrays can store floats, char, doubles, etc. This is because an array is a data structure, which is basically a vessel, and a vessel can hold anything inside it as long it is a valid input.

What are Strings?

A string is basically a collection of objects which are of the char data type, that are arranged in a specific manner. It is important to note that a string itself is an object, but its subparts can be treated as individual objects too.

Strings are sometimes referred to as data structures, however, in Object-Oriented Programming (OOP), strings are mostly considered as objects. 

The memory allocation in the case of a string may vary from language to language, however, there are majorly two ways memory is occupied by a string.

One way is when the memory is already allotted to a predetermined total amount, so any variable appended to the string will just fill up that empty space, and the other one is where the memory occupied increases bit by bit as new variables are being appended.

The former type of string is known as a fixed-length string, while the latter type of string is known as a variable-length string.

Another important characteristic of strings is that strings end with a null character. A null character is denoted by ‘\0’.

This helps determine the string length and often this length is stored as a separate integer which might be used later in the program when one wanted to manipulate the length of the string.

Main Differences Between Array and String

1. The main difference between an array and a string is that an array is a data structure, while a string is an object.
2. Arrays can hold any data types, while strings hold only char data types.
3. Arrays are mutable, while strings are not.
4. Arrays have a fixed length, while strings do not.
5. Arrays do not have a null terminating character, while strings do.

References

1. https://www.nature.com/articles/s41586-020-2649-2
2. https://pdfs.semanticscholar.org/ddac/0f4b8fcc68b0e87dfdf32ec46ce18291d636.pdf