@josephwang , hey. I dont have anything close to a complete answer for you. ButI will try to get the ball rolling. Firstly, I am not sure you are asking the right question. Why you say IDE (Intergrated Development Enviroment) that is a very different thing from asking about the differences of coding in Pythonista vrs to a desktop computer.
I suspect you mean the differences between coding Python in Pythonista vrs on a desktop enviroment. I am just guessing.
Coding in Pythonista as far as UI's go, could be said to be similar if not the same to a desktop. There are many IDE's available on desktops to code Python in. Some are more capable than others. Pythonista, at least to me feels like a nice IDE to work in. It has support for saving code snippets, refactoring code re tabs and spaces, a nice autocomplete implementation. Various navigation tools to move through your files etc. While I dont use a desktop much, I have used various IDE's. Some clearly better than Pythonista and others not not as good. IDE's are normally a very personal choice for people. Some will just use NotePad+ for example. After all you are just creating a bunch of text files with a .py extension.
The other question (the difference about coding between Pythonista and on a desktop) is a lot harder to answer at least for me. I am not sure someone will take on this question here. Maybe they will. Maybe has a good link/resource they can point to.
However, I think for the most part you will be fine in Pythonista. But because you have watched those videos they probably are very desktop centric and I assume they would promote best practices for developing on a desktop. I would say early in the course they show you how to setup virtual environments to work in. As far as I am aware, you cant setup up a virtual env in Pythonista. And its probably not as necessary to have compared to a desktop (ok, that could be argued I guess). But my point is, that there will be differences between your video learning and using Pythonista. Any other issue that was probably covered early in the course is the use of pip to install 3rd party modules. Pythonista itself does not support pip. But some of the nice users here created a shell you can install called StaSh that gives you access to the pip cmd. However because of some iOS rules, you can only pip install pure python modules. Keep in mind, Pythonista ships with a bunch of useful 3rd party libs also, you can see these in the docs.
I will just finish by saying, please dont let my remarks discourage you. It was not my purpose. There are just some differences. I pointed out the 2 above, because I expect they are probably the first differences you will come across (I think) from your video tutorials.
But dont let this deter you in anyway. The differences that exist, do so for a reason. In most cases you should be fine. Eg. The pip example, there is a work around.
I honestly hope I have not confused you. I would have preferred not to tackle the question, mainly because I do not want to discourage you. In terms of the Python coding you learnt in the videos, you should not have a problem. Pythonista supports both Python 2.7 and 3.5, there is an active beta version that supports Python 3.6.
Hope it helps