Python Introducing Lists Using Lists Mutability

Tsering Choedhen
Tsering Choedhen
1,050 Points

Why one arguments is within quotes ("Books") and another one is not when display_list function is called?

When display_list function was defined, it was set with two parameters. And now when this function is called, the two arguments passed. But one argument is passed in a quotes (" ") and another one is not. Why and how will we know that when the arguments passed should be in quotes or not?

3 Answers

All problems are best understood with practical examples, so let's make an example code.

The code

Books = ["Harry Potter and the philosophical stone", "Harry Potter and the dungeon of secrets", "Harry Potter and the prisoner of Azerbaijan"] 

#Let's make a function now

def display_list(display_name_of_book_series, the_list_of_books):
    print(display_name_of_book_series)
    print(the_list_of_books)

#Now let's call the function

display_list("Harry Potter", Books)

The points to take from the example are that

1) The double quotes ("") are used to make a string and anything inside the double quotes ("") will be a string.

2) If anything is a string, it will be taken as it is like, literally, for example, if I put (aposkfj3474734''';;;>><<<<mn(sjsjd) [ a, b ,c,c,v,(polo)] into a string it will be as it is, a practical example;

A_string = "  (aposkfj3474734';;;>><<<<mn(sjsjd) [ a, b ,c,c,v,(polo)]  "

print(A_string)

#Output (aposkfj3474734';;;>><<<<mn(sjsjd) [ a, b ,c,c,v,(polo)]

So anything inside double quotes("") is untouchable. Strings are like a Black Hole it absorbs everything and anything, what if you want to put double quotes ("") in a string, the principle is very simple just put the double quotes("") into triple quotes (""") and you got a string.

example of string;

A_string = ( """The name of the book is 'Harry Potter' and the name of the character is "Harry" is noob""" )

print(A_string)

3) A variable is a name you give or assign to an object ( an object can be anything, it can be a string, a list, a tuple, a number, a function .....) in this case Books is a variable or name assigned to a list of book names. Variables need to be assigned to something otherwise they won't work. an example

#variable      # A string
Books       =  "Books"

4) The display_list function takes two parameters and then prints out whatever is passed in, in this case, I passed in "Harry Potter" as a string and Books as a variable

SO in a summary, regarding your question, the "Books" is just a string and it can be anything you want it to be you can call it "123455" and it won't make a difference because it's a string the Books without the double quotes "" is a Variable and has a value stored in it, so if you put in Book list the program won't be able to find the name Book list because the Variable Book list does not exist.

Ave Nurme
Ave Nurme
14,779 Points

Hi Tsering

In here...

def display_wishlist(display_name, wishes):

  • display_name is just a string, in this case it is "Books" - that's why we put this in quotes
  • wishes is the list which is passed in, in this case it is books on line 1

Does this help?

Tsering Choedhen
Tsering Choedhen
1,050 Points

Thank you Ave Nurme and boi for your explanations.