Data types

Understanding data types

In PHP

In the last section, we discussed how Variables can be used to store various types of data in PHP. Let’s learn about the various types of data that can be stored. 

If you are familiar with other programming languages, you would know that you normally have to tell the computer what type of data a variable can store. In PHP, you don’t have to! But we still need to know what data types we can use.

Let's watch this video

In this video you will learn about different Data Types. Click on play to learn more.

Let's recap

Let’s Recap the video. Data types can be scripted as follows:

(click on the blue arrows for detail on each data type)

This data type can only have values of either “True” or “False”.

This data type can have the value of a signed (positive or negative) integer.

Let's do this together

Let’s practice writing some PHP code. Click on the button below to visit W3Schools coding playground and change the integer from 5985 to something else. Notice how the PHP code sits inside the HTML < body > code in the W3 schools compiler. 

 

Be creative and play around. Click run to see what happens.

This data type can have the value of any rational number. It allows us to store numbers with decimals unlike the Integer data type.

Let's do this together

Let’s practice writing some PHP code. Click on the button below to visit the W3 Schools coding playground and change the float from 10.365 to something else. 

Be creative and play around. Click run to see what happens.

This data type can have the value of a letter, word, sentence, or symbol. Basically it can contain any ordered collection of characters. It can also contain numbers and punctuation marks. Note that all String values are placed in double quotation marks. “The messages that are sent by the dronesare an example of a String Data Type.

Let's do this together

Let’s practice writing some PHP code. We will be writing PHP in our own coding playground or php compiler below. 

Change the values of the variables. Be creative and play around. Click run to see what happens.

Your turn to try

Remember – your task is to help Agent Gail to build the drone software that will help locate spaceship Galaxy X using location coordinates. 

The Galactic Coordinate system locates planets and objects in the Milky Way on lines of latitude and longitude – similar to how we do it on Earth. Do you know what “coordinates” are? 

Coordinates are what GPSs use to locate exactly where you are on the map. We use lines of latitude and longitude to pinpoint an exact location. For instance – Sandton City Mall in Johannesburg is located at: 

  • Latitude: 28.0527° E
  • Longitude: 26.1088° S, 

(We also write latitude and then longitude – that’s the global standard)

If you’d like to read up more about how to locate objects in the Milky Way galaxy –

For the drones to be able to send location coordinates to you and Agent Gail, the drone must be able to first (1) save the coordinates and then (2) send the coordinates. Your first task is ensure that the coordinates are saved then sent.

Here are some steps to guide you:

  1. Create two variable named “latitude ” and “longitude”
  2. Assign the following coordinates to your variables
    • Latitude: -0.97377, 
    • Longitude: -45.64867
  3. Remember the data type of variables is float  (needs to be removed )
  4. Use the echo statement to print the coordinates 
Click on the “fork me” below to edit the PHP code directly.

What data type is the above coordinate?

Click here to find out...

This is a float data type

Let's recap

In this section, we talked about variables and data types and  how they help us store different values. We introduced the following 

  • Variables
  • Data types
  • the different types of data types: 
    • integer: int
    • text: string 
    • numbers with decimals: float
    • true/false: boolean

You built a storage system for the drones to store coordinates.

Next up: Let's learn about arrays

Pain Points – specific problems that prospective customers of your business are experiencing. In other words, you can think of pain points as problems, plain and simple.

 A User – is any person that interacts (by inputs) with a program without having to write the code directly. For example, you are the user to the code that makes your browser/website run. When you clicked on this pop-up, that was the input that made this explanation come up when the code detected it.

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Indentation – In the written form of many languages, an indentation or indent is an empty space at the beginning of a line to signal the start of a new paragraph.

Text editor – is the part of the IDE where you write the code. Most text editors highlight words with different properties like functions to help you distinguish them from one another. 

Homogeneous – of the same kind; alike throughout.

Heterogeneous – diverse in character or content; containing different things

Prompt – to  cause or bring about; to make something happen. For example making someone to say or write something.

Troubleshooting is a form of problem solving, often applied to repair failed products or processes on a machine or a system. It is a logical, systematic search for the source of a problem in order to solve it, and make the product or process operational again.

String Built-in Functions/Methods

There are a lot of strings functions/methods in Python. Find full list in course manual. Here’s are some that you find useful in this course:

Functions

  • len(varName) – Returns the length of a list, string
  • join(varName) – Converts the elements of an iterable into a string.

Methods 

  • varName.capitalize() – Converts the first character to upper case.
  • varName.center(length) – Returns a centered string
  • varName.count(“?”) – Returns the number of times a specified value (?) occurs in a string (varName).
  • varName.endswith(“?”) – Returns true if the string ends with the specified value.
  • varName.find(“?”) – Searches the string for a specified value and returns the position of where it was found.
  • varName.format(placeholder = value) – Formats specified values in a string.
  • varName.index(“?”) – Searches the string for a specified value and returns the position of where it was found.
  • varName.isalnum() – Returns True if all characters in the string are alphanumeric.
  • varName.isalpha() – Returns True if all characters in the string are in the alphabet.
  • varName.isascii() – Returns True if all characters in the string are ascii characters.
  • varName.isdecimal() – Returns True if all characters in the string are decimals.
  • varName.isdigit() – Returns True if all characters in the string are digits.
  • varName.isidentifier() – Returns True if the string is an identifier.
  • varName.islower() – Returns True if all characters in the string are lower case.
  • varName.isupper() – Returns True if all characters in the string are upper case.
  • varName.isnumeric() – Returns True if all characters in the string are numeric.
  • varName.isprintable() – Returns True if all characters in the string are printable.
  • varName.isspace() – Returns True if all characters in the string are whitespaces.
  • varName.istitle() – Returns True if the string follows the rules of a title.
  • varName.ljust(value) – Returns a left justified version of the string.
  • varName.rjust() Returns a right justified version of the string.
  • varName.lower() – Converts a string into lower case.
  • varName.upper() – Converts a string into upper case.
  • varName.strip() – Returns a trimmed version of the string.
  • varName.lstrip() – Returns a left trim version of the string.
  • varName.rstrip() Returns a right trim version of the string.
  • varName.partition() – Returns a tuple where the string is parted into three parts.
  • varName.replace(“old”, “new”) – Returns a string where a specified value is replaced with a specified value.
  • varName.rfind() – Searches the string for a specified value and returns the last position of where it was found.
  • varName.rindex() – Searches the string for a specified value and returns the last position of where it was found.
  • varName.rpartition() – Returns a tuple where the string is parted into three parts.
  • varName.rsplit() – Splits the string at the specified separator, and returns a list.
  • varName.split() – Splits the string at the specified separator, and returns a list.
  • varName.splitlines() – Splits the string at line breaks and returns a list.
  • varName.startswith() – Returns true if the string starts with the specified value.
  • varName.swapcase() – Swaps cases, lower case becomes upper case and vice versa.

String Special Characters

There a number of special string characters that have different functions when used inside ” “. Here’re some useful and common ones:

  • \n – Newline – Everything after it goes to next line.
  • \t – Horizontal tab – creates a tab space, similar to when you use ‘tab’ on keyboard.
  • \b – backspace – deletes the character before the it.
  • \r – carriage return – same as \n

In programming Concatenation is a process of appending one string to another. 

\ – escape character is a string character that tell Python that the next character after it should be taken as a string and not as an instruction.

str ( ) is a built-in function that converts and sequence of characters (numbers especially) in to text. 

Mad Libs is a phrasal template word game created by Leonard Stern and Roger Price. It consists of one player prompting others for a list of words to substitute for blanks in a story before reading aloud.

type ( ) is a built-in function (still to cover what built-in functions are later) that determines the Data Type of any data presented. 

input ( ) is a built-in function (still to cover what built-in functions are later) allows a user to insert info into a program/the code. 

print ( ) is a built-in function (still to cover what built-in functions are later) that executes data inside the brackets. The results get printed out on the console/results section.

Integrated Development Environment – A digital environment used to develop games, software, hardware, that offers integration from debugging to compiling. 

Variables

More about variables

Info about variables

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Let’s hear more about the trends in the software and programming industries, where jobs are moving to and what kind of skills you’ll need in this exciting world of opportunities out there. 

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