hey there! ohk lets start by saying this .
I did try to make a video this time around about list comprehensions but I goofed up and I really need to improve upon my video editing skills before I go through posting any of it online ,so I might have to wait a while to put in a Vlog . I am going to continue where I left. List and working with list.
Till now I have covered how to initialise and work with list. Now some basic operations that list comes . These operations are called methods. getting back to the same example I told you guys before assume that you are going to a market place or Lidl or your local grocery store . So you make a list of things you want buy when you get there . Something similar to what we have here.
So you initialise a list name shopping_list
Shopping_list=[“milk”, “butter”,”Cheddar cheese”, “plain yougurt”]
and now you want to carry out following operations to your list say
- Add a product to the list
- Add multiple products to the list
- Remove a particular product from the list
- or maybe for some god knows reason why … You want the index of a particular product .. You know some people who just have these weird habits or maybe you have OCD . I dont know its your problem. Deal with it!
lets address these issues . Not the OCD one . You still gotta deal with that yourself.
ADDING a (single) PRODUCT to the list
ohk so what you do is use a simple method called append using the following syntax
shopping_list.append(“A pack of beer”)
what this does is add the item “A pack of beer” to the end of the list. So when you try to print out your shopping_list. Using print shopping_list command. what you get is this.
[“milk”, “butter”,”Cheddar cheese”, “plain yougurt”,”A pack of beer”]
someone is having a party tonight .what if you want to add multiple items
ADDING multiple products to the shopping_list .
Now if you want to add multiple items . say haribo and ice creams ,salamis and so on . you can use the following method called extend
so shopping_list.extend([“ice cream”,”salami”,”haribos”]) Does the job for you .It will add it to the end of the these following items. Now remember parameter that you pass to extend have to in the form of an iterable or for now assume it to be same as a list.
now your list looks like this .
[“milk”, “butter”,”Cheddar cheese”, “plain yougurt”,”A pack of beer”,“ice cream”,”salami”,”haribos”]
REMOVING a Product from the list.
You know those days you dream of having a lavish life and then you to peek into your wallet
and you are like .
Yeah you gotta remove those beer can .. sorry man.
so how do you go about it . you use the method called remove and it takes in as argument or parameter the particular element you want remove. so the exact value or item name is needed to be specified.so,
shopping_list.remove(“A pack of beer”)
this result in your shopping list looking like this
>>> [“milk”, “butter”,”Cheddar cheese”, “plain yougurt”,”
A pack of beer“,“ice cream”,”salami”,”haribos”]
it had to be done bro!!! sorry !
now there another method you can call to remove elements either from the end of the list or if you know the index.
shopping_list.pop() removes the last element of the list . so there goes your haribos.
and if you know the index say you know you wrote down butter as the second element of the list. you use
shopping_list.pop(1) second element =index 1 rememeber . which removes your butter from the list …that cholesterol aint gonna go down by itself.
FINDING INDEX of a particular product.
now for the retarded part .
if you wan to know at what index the particular item appears you can use.
shopping_list.index(“salami”) outputs the index number of where salami appears in the list.
by now you must be like SHUT UP ALREADY !!
so I’ll also drop the chalk over here and move to suggesting you to go through this particular exercise of codeacademy to build you basics and get complete grasp over the subject . I sincerely request you guys to through this PARTICULAR TUTORIAL(this is hyperlinked) where they teach you how to traverse through the list . and access each element . I know I haven’t really covered much about machine learning but this is important as this is the base on which you build so .. check this particular link out . Next post I’ll start with pandas and something called as CSV files .. so keep up .