Just A Turtle Coding. @turtlingturtlousturtle-blog - Tumblr Blog

Tuples :D

So we talked a little bit of lists and compared it to tuples, but what exactly is a tuple?

A tuple is basically a list that you cannot modify. If you create a tuple named grades and plugged in your grades of this partial, those grades will not be modifiable.

How to create a tupple? You only need to put in the name and use () instead of [].

Example = (1,2,3,4,5)

That way, if you print Example(1), it will return 2 but you cannot modify it later in the program, that’s why programmers rarely use tuples, since they cannot be modified.

Lists

What does a list means? Basically Python has a type of data that’s named list that’s closely related to a tuple. It is basically the same but we use [] instead of (). The only difference is that a list can be modifiable “on-the-go”.

A list can be created by typing the name and adding some values, it will be indexed starting from 0

Let’s say that my friends are called Juan Pancho and Roberto

friends = [”Juan”,”Pancho”,”Roberto”] then Juan would be 0, Pancho 1 and Roberto 2. If I call to print friends[1], it would return Pancho.

I could also say that friends[1] = Paco, that would modify the value of Pancho and change it to Paco instead.

More info on: http://sthurlow.com/python/lesson06/

Deciding repetition

How to know which type of repetition to use... It’s a great question for programmers.

One factor to take into account is the space you are allowed to use, how many bytes or megabytes or gigabytes are you allowed to use?

Another factor to take into account is the length of the program and if you could make it shorter. A factorial can be made simpler if done with a repetition algorithm rather than using nested ifs or nested loops

One last factor to take into account is how simple it is for humans to read. If you just nest loops then it might be more complicated than if using a for loop.

Dictionaries

Yeah, you can have dictionaries in Python... To create them it’s really easy, you type in the name and then start adding the elements. It is important that you type in the key:object since the key is what will define that value/string/object.

It is called dictionary because of the resemblance it has with a real dictionary where you read the word and its meaning.

You can have as many dictionaries as you like, you only have to remember the name and the key; or you could just call the dictionary and it will print it.

Remember that you can create dictionaries whenever you like.

More info on this topic on: http://christa-vanilla98.blogspot.mx/

Physics

Owner did a project with Francisco Marquez, check it out here:

https://firstprogrammingsteps.wordpress.com/2016/10/23/physics-homework/

Validating entries :D

When validating user entries, you have to know what you’re looking for. When a function uses a specific type of variables, it might crash if the user inputs something that the function can’t use. To apply this, you can call a try function.

For more info, you can consult: http://stackoverflow.com/questions/23294658/asking-the-user-for-input-until-they-give-a-valid-response

while True: try: # Note: Python 2.x users should use raw_input, the equivalent of 3.x's input age = int(input("Please enter your age: ")) except ValueError: print("Sorry, I didn't understand that.") #better try again... Return to the start of the loop continue else: #age was successfully parsed! #we're ready to exit the loop. break if age >= 18: print("You are able to vote in the United States!") else: print("You are not able to vote in the United States.")

Ranges

Ranges are used a lot in for loops, but understanding them is key to knowing how to program.

A range basically tells Python from which number to which number it should read.

As long as the variable is a number, you can use it in a range.

for x in range (8) print(x)

it would print 0,1,2,3,4,5,6,7,8 since Python starts from 0.

You could use another notation to tell Python how to read the range.

for x in range (A,B,C)

where A is the start number, B is the end number, and C is the period in which Python should read it. If you want a number to go negatively, you have to use C value as -1. It should look like this: for x in range (0,-10,-2) print(x)

0,-2,-4,-6,-8,-10

Here’s more info about the topic:

https://www.youtube.com/watch?v=fhCAt0s27no

Recursive functions

So a recursion function is when a function is called inside the same function. Using them can reduce your code from 100 lines to maybe a 20-line code.

Something that’s recursive in its own definition is a factorial function. When using recursion functions, it’s really easy to program a factorial.

You can learn more from this topic in: http://stackoverflow.com/questions/4502429/recursive-factorial-function

How to read love.txt

To use saved variables you have to use an open function.

In: http://www.pythonforbeginners.com/files/reading-and-writing-files-in-python you could have a better explanation of how to to this, since it’s a pretty complicated topic.

Files can be either binary or text and the way to open them is: file_object = open(filename, mode) where file_object is the variable to put the file object.

Love lasts forever, variables don’t

Owner taught me that variables can be like love... Love can either last for one moment, or forever... and so can variables, but for variables to last over time you have to save them.

How to save variables you might be wondering:

file = open("newfile.txt", "w") file.write("hello world in the new file ") file.write("and another line ") file.close()

These files could use bytes or even gygabytes. There’s lots of ways for reading them tho... but that’s for another post.

When in doubt, go back to yourself.

So recursion is a useful resource in Python. It will save you lots of lines of code, bytes of memory and lots of time. Here’s how you do it:

#Python #LastMinutePost #GodHelpMe

Factorials again!

So here’s another use of the for loop, you can use it to calculate the factorial of a number.

#Python #LastMinutePost #GodHelpMe

Multiplying Stuff

A quick tutorial on how to make the factorial function using a while loop.

First you have to state a counting variable for it to go through the while loop, you also have to declare a variable where the total will be stored.

Then it’s just a piece of cake, you have to multiply the variable where the total is being stored. Important note, the variable with the total can’t be 0, it has to start at 1 for it to be multipliable.

#Python #LastMinutePost #GodHelpMe

Using Elif

Owner taught something about ifs and elses but what’s the difference between an else and an elif?

It’s easy, an elif statement has no limit as to how many of them you can put without indenting them.

For example, the elif compares something when the condition wasn’t met but there’s another condition to check.

This is only a simple post but I hope it clarified some doubts.

#python #lastminutepost #godhelpme

L-oopsie

In Python, you have 2 types of loops. Both have different uses, Some you use when you know what and how many times you want it, other you use them when you’re like me, you don’t know how many times you’ll want it.