Arrays in Python / Numpy

Arrays are collections of strings, numbers, or other objects. This tutorial demonstrates how to create and manipulate arrays in Python with Numpy.

[@ayouberrazki5602]

oh god finally english

[@kevin_kk]

I know 😄

[@chaunceya648]

@@kevin_kk I mean, being honest. All the tutorials I find are English....they're just in accents that are impossible to understand.

[@coolmonkey619]

LOL!!!

[@5staryzzz]

Ikr😂

[@kayzao2079]

lmao

[@omarpro8626]

Ive been searching for this for 2 hours! Thanks alooot ❤❤

[@jonathansum9084]

I can tell you that ur video is way more simple and easy to understand.

[@MrPDawes]

Having never programmed in Python before, this is really a good introduction to the IDE, and basic variable/array manipulation. I like languages which are not strongly typed having grown up with BBC BASIC. Found reference to Numpy in some example code for SenseHAT code on Raspberry PI and hadn't a clue what it was. I learned more in this one tutorial than all the weeks looking at code. I'll definitely be looking out for more Tutorials by APMonitor.

[@rrc]

Thanks, Peter. There is more Python material at my introductory course for scientists and engineers: apmonitor.com/che263

[@snail8720]

But... Those are lists... Not arrays. A list, unlike an array, doesn't have a defined data type for its objects, nor does it have a fixed size...

[@ericka95]

You are amazing thank you so so much !

[@happyfignes4392]

Thanks for the lessons, I am new in Python and installed only ANACONDA, however cant find IDLE on my start menu. is it something wrong with my installation? thank you.

[@apm]

Here are videos that show how to install IDLE from Python.org: apmonitor.com/pds/index.php/Main/InstallPython

[@sujaysinha81]

Very nice

[@LaurenAnne6]

Very helpful.

[@user-rn5qz9eo1f]

Thanks a lot ,a pretty good tutorial to follow

[@qzorn4440]

great information. thanks.

[@williamswilmanalvarezzabal6064]

I understood you can init an empty array with a determined dimension also you can fill the array with ones, zeros, etc but how can I init that array with -1 value?. Thanks in advanced

[@apm]

np.ones(100)*(-1)

[@awaraamin9670]

a good one thank you!

[@pratikkandalgaonkar5791]

Thankyou man 👍

[@apm]

No problem 👍

[@maxschnepf8977]

nice totorial. is there a possibility you could filter this high backgroud frequency out? i could enjoy it even more then

[@apm]

I record videos on a Surface Pro laptop. The computer fan sometimes kicks on mid-recording leading to a fan noise in the background. kzbin.info/www/bejne/j321h42OmsmGosU I probably just need to get an external microphone - thanks for the suggestion.

[@Bruili]

I think what you call array is called list

[@apm]

+B'ur You are correct that within base Python, arrays are called lists. Within the math community, arrays can either be vectors (1D) or matrices (2D+). See lpsa.swarthmore.edu/BackGround/RevMat/MatrixReview.html for my working definition of arrays.

[@alexandra-stefaniamoloiu2431]

Your tutorial is about python data structures not mathematics. You should be more attentive to the vocabulary.

[@apm]

I appreciate the suggestions. In the future I'll use both terms to avoid confusion.

[@rodolfoalvarez7141]

Thank you for the video.. I agree with Alexandra it is very important the vocabulary to avoid more confusion :)

[@rodolfoalvarez7141]

"An array is a data structure that stores values of same data type. In Python, this is the main difference between arrays and lists."

[@witneyh9353]

Hi I am unable to find how you can get the user to print the data from the array they want. For example "Red" "Blue" "Yellow" red is 0, blue is 1, yellow is 2. User enters that they want to print "1" print: Blue. How can you do this?

[@apm]

colors=['red','blue','yellow] print(colors[1]) Is this what you need?

[@witneyh9353]

thank you for your response! I managed to do it like this :)

[@mr.melomaniacnextdoor6840]

Won't x[1] be 3 in 0:53?

[@apm]

The x[1] indicates that we are taking the 2nd element of the list (or array). The second element has a value of 1 because it is [0,1,2,3,4].

[@mr.melomaniacnextdoor6840]

@@apm ok thanq 😊

[@vijayalakshmi6028]

Hi, I typed the same program but it gives an error "no module name numpy"

[@apm]

+vijaya lakshmi you need to install numpy. Here are instructions for Windows: kzbin.info/www/bejne/Y53PeYyLgq1sesk

[@brianholbert2080]

THese are lists, not arrays, Python has no array data structure built in.

[@apm]

You are correct. Please see the other helpful comments on this video.

[@matthewjames7513]

Thanks for the video! I'm trying to calculate the perimeter of a parabola. I can easily plot it once I define x and y: x=np.linspace(0,1,100) y=x*x but how do I separate out individual x and y values so that I can find the distances between them? Cheers :)

[@apm]

You can separate out the elements by referencing: x[0] x[1] . y[0] y[1] . etc In a "for" loop, just use something like: for i in range(100): print(x[i]) print(y[i]) Here are some tips on finding an analytic solution to your problem: math.stackexchange.com/questions/229642/length-of-a-parabolic-curve

[@sibazazo9208]

thanks for the video it was very helpful i noticed that you're running python on windows 10 and i am wondering if you have any information about installing openfst toolkit on windows with python 3.6 i tried to install it using anaconda with " pip install openfst" but i got this error: cl : Command line error D8021 : invalid numeric argument '/Wno-unneeded-internal-declaration' error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\VC\\BIN\\x86_amd64\\cl.exe' failed with exit status 2 could you help me please if you have any information about this matter

[@apm]

It looks like PyPI only has source tar.gz and that you'll need to get the right compiler and options. Sometimes developers make a package that is easy to install with Linux or MacOS but can be difficult to create a binary on Windows. I like this collection of Python packages for Windows but it looks like openfst is not on the list: www.lfd.uci.edu/~gohlke/pythonlibs/

[@sibazazo9208]

i search this link for openfst before and i didn't find it are you saying that there is no other way to install it on windows?? or is there any other package like openfst for windows with the same commands?

[@apm]

Yes, you'll need to compile it yourself. There is no Windows binary for this package. Here is some additional help on Windows compilers for Python: wiki.python.org/moin/WindowsCompilers

[@sibazazo9208]

sorry for disturbing you but i am new to python and i searched for days for a solution and i didn't find any i tried installing a precompiled openfst version but i didn't know for sure what to do with it i tried to compile it using visual studio and there was no error and i tried adding the debug subfolder to the user PATH but when i tried to import openfst in python interpreter it didn't work i also tried to transfer the package folder to python folder but none of the previous solutions helped could you please tell me what i have to do with the precompiled package so i can import it in the python interpreter sorry again for disturbing.

[@rrc]

Siba Zazo, normally you need a whl file or else compile the package yourself from source. Have you found a whl file? Here are more tips: apmonitor.com/pdc/index.php/Main/InstallPython

[@slickwillie3376]

You started with list, not array

[@slickwillie3376]

Although, coming from another language you prolly are used to calling things like python lists "arrays" since they are similar.

[@hisokamorow4082]

python 3??????

[@apm]

Check out the new material for Python 3: apmonitor.github.io/begin_python

[@arhamansari1312]

Excellent

[@pothurajuashesh7165]

2 dimensional array?

[@apm]

An array is "an ordered series or arrangement". I'm defining a vector as a 1-D array, a matrix is a 2-D array of values. Higher order arrays can also exist in NumPy.

[@deojeetsarkar2006]

thats a list

[@apm]

Thanks for the clarification. They are lists in base Python but are called Arrays / Matrices in scientific Python packages such as NumPy.

[@deojeetsarkar2006]

@@apm means there's a lot more to study now :(

[@prateeksaurabh]

@@apm How can list be called a array. Aint they completely different concept?

[@garrett3883]

how do I get numpy.

[@apm]

Here are tips for installing NumPy: apmonitor.com/pdc/index.php/Main/InstallPython

[@garrett3883]

thanks

[@glamourtimeglamsquad6805]

B

[@hstevens1125]

Need to zoom in

[@apm]

Thanks for the suggestion. Text editors like Python IDLE don't have a zoom feature. I like to use Notepad++ for code zoom so that it is easier to see the text in the videos.

[@5staryzzz]

@@apm What you can do is, go to options>configure idle, and then change the size

[@apm]

@@5staryzzz Thanks!

[@5staryzzz]

@@apm Welcome!

[@JoseGarcia-px9xj]

did you know what this expression do (pt.numpy())

[@apm]

No, I haven't seen that before.

[@PeteDork]

You kinda sound like H. Jon Benjamin aka Bob from Bob's Burgers

[@apm]

Thanks! I've heard that I sound a little like Matthew McConaughey but I also like your suggestion.

[@gol1723]

This is a great video, too bad that it calls the lists, arrays. Coming from a Java background I was confused for a good couple of hours.

[@ghosthunter9897]

Man this is not an array. It's a list. Dont fool people!

[@apm]

Thanks. A few others also made this comment. You are correct that this is the right Python terminology.

[@larsmonstad]

Buy yourself a new mic

[@apm]

Thanks for the suggestion. I did get a professional recording mic a while back and the results are much better.