DEV Community: Lisa Ghosn

User Input() and Outputs

Lisa Ghosn — Sat, 11 Nov 2023 18:38:11 +0000

User input() is an interactive function that allows the user to insert a value into your program.

An Output is the resulting data produced from the input.
print() is an example of an output function. It is used so the program can display the resulting data and/or communicate with the user.

Let's create the code for the photo banner above, as a user input example:

name = input('PLEASE ENTER YOUR NAME')
message = f'HELLO {name}! AND WELCOME!'
print(message)

The program has asked for John's name in order to communicate a welcome message to him.

There are implicit and explicit data type conversions in python. Inputs will always produce a string unless otherwise stated, this is an implicit (automatic) conversion.

If you would like an input to produce a different data type, it will need to be explicitly instructed, for example;
age = int(input()) - will convert the input into an integer.
We can check data types with the type() function;
print(type(age)) - will check what data type the value in your variable is.

Other examples of implicit and explicit conversions:

/ will implicitly produce a float and // will implicitly produce an integer. Also, math operations between an integer and a float will always produce a float.

F-Strings

Lisa Ghosn — Fri, 03 Nov 2023 14:09:35 +0000

I'm keen to see how f-strings work with the programme I wrote in my previous post. I was advised that they're much easier to work with and less prone to error.

so...

I have a lot of boxes of eggs in my fridge and I want to calculate how many omelettes I can make. each box of eggs contains six eggs and I need four eggs for each omelette.

'to make 25 omlettes, you will need 100 eggs. That means you need to buy 16 cartons of eggs'

'there are 54 eggs in total, this means you can make 13 omlettes with 2 eggs left over'

It's a lot easier to figure out which placeholder represents which variable, so the code is a lot easier to read. I'm also happy to see the code shrink a bit!

Python in Practice

Lisa Ghosn — Wed, 01 Nov 2023 18:34:16 +0000

Here are some exercises that I was working on this week:

Bug 1

I am building some very high quality chairs and need exactly four nails for each chair. I've written a program to calculate how many nails I need to buy to build these chairs but something is wrong.

chairs = '15' nails = 4 total_nails = chairs * nails message = 'I need to buy {} nails'.format(total_nails) print('You need to buy {} nails'.format(message))

When I run the program it tells me that I need to buy 15151515 nails.

How do I fix it?
To correct the code, I need to change the variable; chairs, from a string into an integer. In order for me to do that, I need to remove the apostrophes on the value 15.
once this is done, the program will run correctly and tell me that I need to buy 60 nails.

Bug 2

I'm trying to run this program, but I get an error.

my_name = Penelope my_age = 29 message = 'My name is {} and I am {} years old'.format(my_name, my_age) print(message)

How do I fix it?
To correct the code, I need to make Penelope a string:
my_name = 'Penelope'

python hasn't recognised the data type that the value Penelope is and isn't sure how to proceed. Once we specify that this is a string using '' it will run as instructed.

Program 3

I have a lot of boxes of eggs in my fridge and I want to calculate how many omelettes I can make. each box of eggs contains six eggs and I need four eggs for each omelette.

number_of_eggs_for_omlette = 4
number_of_eggs_in_carton = 6
number_of_egg_cartons = 9
total_eggs = number_of_egg_cartons * number_of_eggs_in_carton
omlettes = total_eggs // number_of_eggs_for_omlette
left_over_eggs = total_eggs % number_of_eggs_for_omlette
message1 = 'there are {} eggs in total, this means you can make {} omlettes with {} eggs left over '.format(total_eggs, omlettes, left_over_eggs)
print(message1.format(message1))

There are 54 eggs in total, this means you can make 13 omlettes with 2 eggs left over

I also want write a program to tell me how many eggs I need to buy to make x amount of eggs. For example, I want to make 25 omlettes, how many eggs do I need to buy??

number_of_eggs_for_omlette = 4
number_of_desired_omlettes = 25
number_of_eggs_in_carton = 6
total_eggs_needed = number_of_eggs_for_omlette * number_of_desired_omlettes
egg_cartons = total_eggs_needed // number_of_eggs_in_carton
message2 = 'to make {} omlettes, you will need {} eggs. That means you need to buy {} cartons of eggs' .format(number_of_desired_omlettes, total_eggs_needed, egg_cartons)
print(message2.format(message2))

To make 25 omlettes, you will need 100 eggs. That means you need to buy 16 cartons of eggs

These programmes will print the information that I need, depending on the values i'm inputting into it.

Data Types, Operators and Variables

Lisa Ghosn — Wed, 01 Nov 2023 15:53:34 +0000

（￣︶￣）↗　Basic Data Types

Numbers

Integer (int()): a python data type for whole numbers.

Float (float()): a python data type for decimal numbers.

(also Booleans (bool()), but we'll get on to them a bit later)

Other ways to record numerical data

Binary (bin()) is how computers best process information using 1's and 0's, to the power of 2.
Hexadecimal (hex()) is a mixture of numbers and letters and is used to condense binary code and data, to the power of 16.
Octal numbers (oct()) also condenses data to the power of 8.

Strings

String: a string is a python data type for text and characters contained within either "" or ''.

Using "speech marks" might be better to avoid confusing Python. If apostrophes are used during a word then the whole string may be misread, for example;

print('it wasn't what I needed')

Python has misinterpreted the apostrophe in the word 'wasn't' as an instruction to end the string.

Strings can have spaces within them but variables need ‘_’ i.e snake_case (common practice) to define a space; variable_name = value

Variables are labels used to define the value of the data stored within them. Variable names and values are connected with the = sign. Variable names cannot start with a number but can include numbers i.e.

student_1 = Casey

Algorithmic Operator Types

+ add
- subtract
* multiply
/ division
** exponent
% modulo (remainder)

The * and + operators work on strings as well as integers. the * will repeat a string and the + will join the two words together. This is called concatenation.

HTML, CSS and JS - a silly little game

Lisa Ghosn — Wed, 01 Nov 2023 15:43:28 +0000

Move your mouse carefully through the blue line and safely into the pink square. if you fail, the computer will taunt you BUT IF YOU WIN...