[Music] welcome back aliens my name is Ivan jetty and let's continue this is on Python the till is fine we have talked about numpy right but there's still one question we have talked about numpy three to four videos before and then the reason we started with numpy is by talking about multi dimensional array and till this point we have not touched it you know so that's the awesome thing about numpy other than multidimensionality we have so many features right but in this video finally we are talking about multi dimensional array now what is multi dimensional so we have sympathy right we have one dimensional we have two dimensional we can create three dimensional now with that I want to perform certain operations right so in this video we'll talk about two dimensional and what what operations you can perform here okay so let's create our two dimensional array okay so we got an array and then since with the moment you say you want to create multi dimensional array you need to use this symbol right so this is one array so this is one big array which you have and inside this one big added you want two different arrays and that's the idea right if you have one array with multiple elements that's one adding if you have a big array inside that either you have added itself that is multi damage or two-dimensional array right so this one this is one big added right and in this one big added you have to mod Ares so you will say we have two more a days and each array will have certain values I would say 1 comma 2 comma 3 right and the secondary will have 4 comma 5 comma 6 so what we have here is we have two dimensional adding ok now how do you know how do you know that this is two dimensional so if you have an array and if you want to check first of all it splits print the array as it is I would say ARR one run this code and you can see we got an array so this is the output so we got one big array inside that we have two arrays so there are certain functions you can apply here the first function is called as D type now using T type you can guess you can know you will know what type of data you are working with so at this point we are working with paint we have another keyword or the attribute you can say which is ending now ending is dimension which will give you the number of dimensions and you can see the output it is 2 so when you work with single we'll give you one when you say three dimensionally it will give you three right so it will give you the number of dimensions you have and plus it is also called as ranking so it will write so it is one Deanna is it 2d or 3d array now we have one more which is called a shape so I will say shape here now what shape will give you as let's run this so shape says 2 comma 3 drawn what it means it will give you the number of rows and columns so we have 2 rows and you have three columns so it will give you tuple with number of rows and number of columns the other attribute we have a size now using size it will tell you the size of the entire block and you can you can count it now so we have 3 and 3 to the 6 so that's 1 and you can see we got 6 so there are other so there are multiple meters you can use right in fact we have one function which is awesome example if I have an array which is a or r2 and I want to create another I want to create this added to with the help of an array 1 but this should be this should be 1d array ok so how can you convert a 2d adding to 1 DL it's very simple you say al L 1 dot there is a function called as flatten so the moment you say planner it will flag the added right so from two dimensions you will get one dimensional law and I went to print of course the arr2 and if you on this code you can see we got one dimensional space so you can create from multi-level single dimensional how about from single dimension of multi-dimensional because now this is so era 2 is one dimensional right I want to create three dimensional how can we do that now first of all to make it three dimensional I want to have some more values of course then it will work right that is a two again and nine so we got six values here and let me take six values zero as well because 6 plus 6 is 12 and it is easy to create a two-dimensional array when you have this number of values so I will create an a3 and this should be a two-dimensional array from one damage now I want to create a two-dimensional array so you will say air are 2 dot the function name is reshape so you can convert a single dimensional array into 3d array ok but then what you to pass you so when you say you want to be a 3d array you need to pass the number of so let's let's try with two-dimensional first and then we will go for three dimensional so I would say three here I went to print three now you have to pass the number of rows and columns so i would say i want three rows and the number of columns will afford right so we have three into four twelve so we have three rows and four columns if I run this code you can see from 1d Arabic or 2d array so we got three toes and we got four columns now it is also a Thule because in an Eddie so the outer and it has single dimensional arrays right now what if you have a big a day in which you have two deities okay I know that's that's pretty difficult to understand but let's try it out so I will say 2 comma 2 comma 3 so 2 comma 2 comma 3 is 12 right so 22 is 4 4 into 3 is 12 now what it will do is it will create a 3d array ok big 3d a D and that treaty array will have 2 dimensional array so it will be having 2 2 lemmas parity and each 2 dimensional array will have 3 values or two-a-days with three 3 values ok let me select measure on this point for you so you can see this is what I'm talking about it it will give you a 3d array and this treaty array will have to 2d Ally so you can see this is one 2d array this is 2 second to the ADI and each 2d array will have 2 and it's 2 and is added to 1d array and then each one D Ally will have D values that's what you're saying we got to we got one big a D which has two two-dimensional array which has to do two single dimensionality and then we charge three values okay so that's what if you have to say and you've got the output here so this is some function you can apply to perform certain operations on to the added now once we talked about to rearrange some operations the main thing about mathematics you know we have a concept when you talk about arrays in mathematics we have a concept of mitosis I'm sure you are you have done that in your college right now when you talk about matrices what is my choice you can imagine a two-dimensional array right so we have multiple rows and multiple columns now we can have one row and multiple columns right way we call them as low matrix right or we can have a polymer matrix which has multiple roles but single column but ultimately you can represent that with one D added right so even if you have one row one column you can say that's one day what if you want to have to do a metric matrix format you know value for those multiple columns we can do that here in fact the array the other elevation which we are working with this one this is a 2d area right so I will just remove all this stuff and I will put I want to print one and I don't want all this values here let's reduce it we can have 2 rows and 4 columns so if you have this quote this is your matrix right but then to actually work with metrics there are certain operations we can perform so you have to convert this to Deanna into a matrix format and the way you can do that is by saying matrix m is equal to there is a function called as matrix and in this matrix you have to pass a r1 so you pass a 2d array it will give you a matrix format let's run this code and this is your matrix also it's not this one let me print em so this is your matrix I know the output looks similar right output is almost same what is difference is with this M you can perform more operations the operations which we do in matrices now this is not the only way of putting a matrix example if you don't have or two-dimensional if you have a string with you maybe you're you you are taking input from the user in that case you will pass you will say hey I got a value 1 I got a value - I got a value 3 and value 6 now how can I differentiate between two tools here you just have to give a semicolon at the end and then I canes have to say 4 comma 5 comma 6 comma 7 and even this works if I'll in this code so you can see when this works you don't need a separate a date to save the value you can simply on this quote an acquaintance a still works if you want to create multiple rows I mean for those and two columns you can just give a semicolon after every two values so this will convert it into for those and two columns right so regard for those on two columns so let me just do some modification here because we want to perform some operations here I would I will say three rows and three columns so you can see we got nine values we have three rows and three columns if I run this code this is what you've got right now there's a concept of diagonal elements what if you want to have diagonal diagonal element here I don't want to print all and the entire matrix I just want to print the diagonal which is 1 4 7 you can do that with them with a function called as diagonal just say diagonal and pass em and you're good to go you can see we got all the diagonal elements so this is fun so if you have metrics you can perform this off in fact not just this one but what if I want to look let's try so I will say m dot so there is a function called as min so you know the answer right so when you say min it means the minimum element so in this code that is your one of course and if you say max it will give you the max element so the opposite which we do with a DES can be done with mattresses as well but with my Trice's you get this amazing power now if you remember if you have done with matrix before if you have worked with matrix before we have this concept of adding two matrices that is very easy right you simply have to add the elements the problem starts when you want to multiply two matrices now if you are thinking if you want to multiply two matrices simply take the values from here simply take the values from here multiply that's not the case in multiplication of matrices you have to do some of those and column combinations right if they remember matrices if you have not done that before I would suggest you to watch my video on how to multiply two matrices so you will find the link in description right here but once that video if you are not done data if you know how it works how are you doing programming in fact if you have done C C++ Java before you know we have to use multiple loops to make it work right so if you if I ask you to hey you need to multiply two matrices go with C programming you know it will take entire one page that's not the case with Python here what Python says is if you have two might Rice's that's well encode let's create another matrix here let's call this M as M one and regard this is M two we can change the values of course I will I will say this is 2 this is it doesn't matter you can have the same matrix or different one I want to might apply this it's very simple you curate m 3 equal to m1 into m2 now this is not a simple multiplication ok first let's try with addition if this if that works and at the end I will print m3 ok let's run this code and you can see it works you are adding two matrices it's it's straightforward right you can just you can just see the combinations there but what if I say multiplication now this is not a normal multiplication ok so if you see the output it's not normal multiplication it's not 1 into 1 it is not 22 it is something different so this is where you add you multiply Row with column combinations right now this is done automatically in matrices and that's that's the amazing thing about Python we have so many stuff available right so it suggests you do this manually also so as assignment you can you can do matrix multiplication but manually now how would you know the logic of it so in the description area there's all the video in that I have talked about the theory of it how to multiply two matrices just look at that video and try to convert that into algorithm and try to convert that into a code in Python okay not using this simple multiplication so that's it that's how you might apply matrices let me know in the comment section if you have any questions and if you are enjoying this video let me know in the comment section as well Duke I like but I've been trying it thanks for watching everyone bye you