Skip to main content

Data Types in Python

Data Types


Data types are the key for any programming language. Various data types are present to do different operations and variables can store the corresponding data.

One of the greatest advantage for python is it is dynamically typed (i.e., data type is assigned during the run time based on the value assigned). 

Unlike most of the programming languages, there is no need to define a variable with data type explicitly mentioned. 

Below are different categories of data types in python. 

  • Numeric
  • Sequence 
  • Boolean
  • Dictionary
  • Set

Let's have a look at the data types in each of these category. 

Numeric:

  • int - integer data type, to hold the whole numbers. No decimal values are stored in integer data type. This can hold both Positive and Negative values.
  • float - float data type, to hold the numbers along with decimal values. This can hold both Positive and Negative values.
  • complex - complex data type, complex numbers are a combination of real numbers and imaginary number (multiplied with 'j' (square root of -1)).

Numeric data types in python

Sequence:

Data stored as a sequence in a variable (or collection of data of same data type or different data type). 
  • str - string data type, String is considered as collection (or array) of characters.
  • list - List is a collection of data, This can hold data of different data types. Lists are specified in square brackets.
  • tuple - Tuple is a collection of data, This can hold data of different data types. Tuples are specified in round brackets.

Sequence data types in Python

We can see that List and Tuple both look same except the way they are defined. 

So, What's the difference between List & Tuple? Data in List can be updated, removed or new data can be added to the list. Where as Once defined, data in the tuple cannot be amended.

Tuple is the best choice when there is a set of values and they don't change through out the program (like constants) and Lists are flexible and can be used for any kind of transaction processing. 

How can we access individual data elements? Individual element of a string, list or tuple can be accessed using index. Index starts from '0'. 

Sequence data types in Python


Same way, data can be accessed in reverse as well, Last element would represent the index '-1'. 

Sequence data types in Python

Boolean:

  • bool - Boolean data type, to hold the boolean value i.e., True or False. This can only take 'True' or 'False' (case sensitive).
Boolean data type in Python

Dictionary:

  • dict - Dictionary data type, this hold a set of data with key and corresponding value separated by ':'. Data in dictionary can be accessed by using key and it has no corresponding index. Data in dictionary is enclosed in curly brackets.

Dictionary data type in Python

Set:

  • set - Set is a un ordered collection of data of different data types. Data cannot be accessed by using index. But, the elements of a set can be access through loop or by value. Data to a set can be assigned from List or tuple using 'set' function. 
Set data type in Python

We have seen how to assign the data to a variable and how it determines the data type based on the data assigned in the code samples above. But, haven't really seen much about variables and I will share more details on variables in the next post.


If you have any Suggestions or Feedback, Please leave a comment below or use Contact Form.
Labels:

Comments

Post a Comment

Popular posts from this blog

All about READ in RPGLE & Why we use it with SETLL/SETGT?

READ READ is one of the most used Opcodes in RPGLE. As the name suggests main purpose of this Opcode is to read a record from Database file. What are the different READ Opcodes? To list, Below are the five Opcodes.  READ - Read a Record READC - Read Next Changed Record READE - Read Equal Key Record READP - Read Prior Record READPE - Read Prior Equal Record We will see more about each of these later in this article. Before that, We will see a bit about SETLL/SETGT .  SETLL (Set Lower Limit) SETLL accepts Key Fields or Relative Record Number (RRN) as Search Arguments and positions the file at the Corresponding Record (or Next Record if exact match isn't found).  SETGT (Set Greater Than) SETGT accepts Key Fields or Relative Record Number (RRN) as Search Arguments and positions the file at the Next Record (Greater Than the Key value). Syntax: SETLL SEARCH-ARGUMENTS/KEYFIELDS FILENAME SETGT  SEARCH-ARGUMENTS/KEYFIELDS FILENAME One of the below can be passed as Search Arguments. Key Fiel
4 comments
Read more

What we need to know about CHAIN (RPGLE) & How is it different from READ?

CHAIN READ & CHAIN, These are one of the most used (& useful) Opcodes by any RPG developer. These Opcodes are used to read a record from file. So, What's the difference between CHAIN & READ?   CHAIN operation retrieves a record based on the Key specified. It's more like Retrieving Random record from a Database file based on the Key fields.  READ operation reads the record currently pointed to from a Database file. There are multiple Opcodes that start with READ and all are used to read a record but with slight difference. We will see more about different Opcodes and How they are different from each other (and CHAIN) in another article. Few differences to note.  CHAIN requires Key fields to read a record where as READ would read the record currently pointed to (SETLL or SETGT are used to point a Record).  If there are multiple records with the same Key data, CHAIN would return the same record every time. READE can be used to read all the records with the specified Ke
Post a Comment
Read more

Extract a portion of a Date/Time/Timestamp in RPGLE - IBM i

%SUBDT Extracting Year, Month, Day, Hour, Minutes, Seconds or Milli seconds of a given Date/Time/Timestamp is required most of the times.  This can be extracted easily by using %SUBDT. BIF name looks more similar to %SUBST which is used to extract a portion of string by passing from and two positions of the original string. Instead, We would need to pass a value (i.e., Date, Time or Timestamp ) and Unit (i.e., *YEARS, *MONTHS, *DAYS, *HOURS, *MINUTES, *SECONDS or *MSECONDS) to %SUBDT.  Valid unit should be passed for the type of the value passed. Below are the valid values for each type. Date - *DAYS, *MONTHS, *YEARS Time - *HOURS, *MINUTES, *SECONDS Timestamp - *DAYS, *MONTHS, *YEARS, *HOURS, *MINUTES, *SECONDS, *MSECONDS Syntax: %SUBDT(value : unit { : digits { : decpos} }) Value and Unit are the mandatory arguments.  Digits and Decimal positions are optional and can only be used with *SECONDS for Timestamp. We can either pass the full form for the unit or use the short form. Below i
2 comments
Read more