I am using openpyxl to read an excel file that will have changing values over time. The following function will take string inputs from the excel sheets to make frames for Tkinter.
def make_new_frame(strng, frame_location, frame_name, frame_list):
if not(frame_name in frame_list):
frame_list.append(frame_name)
exec("global %s" %(frame_name)) in globals()
exec("%s = Frame(%s)"%(frame_name, frame_location))
.... etc.
The code itself is quite long but I think this is enough of a snapshot to address my problem.
Now this results in the following error while parsing:
SyntaxError: function 'make_new_frame' uses import * and bare exec, which are illegal because it is a nested function
Everything in the code I included parsed and executed just fine several times, but after I added a few more lines in later versions in this function, it keeps spitting out the above error before executing the code. The error references the third line in the function, (which, I repeat, has been cleared in the past).
I added "in globals()" as recommended in another SO post, so that solution is not working.
There is a solution online here that uses setattr, which I have no idea how to use to create a widget without eventually using exec.
I would really appreciate if someone could tell me how to bypass the error while parsing or provide an alternative means for a dynamically changing set of frame names.
Quick Note:
I am aware that setting a variable as global in python is generally warned against, but I am quite certain that it will serve useful for my code
Edit 1: I have no idea why this was downvoted. If I have done something incorrectly, please let me know what it is so I can avoid doing so in the future.
I think this is an X/Y problem. You are asking for help with solution Y instead of asking for help on problem X.
If your goal is to create an unknown number of Frame objects based on external data, you can store references to the frame in a list or dictionary without having to resort to using exec and dynamically created variable names.
exec is a perfectly fine function, but is one of those things that you should never use until you fully understand why you should never use it.
Here's how to solve your actual problem without using exec:
frames = {}
def make_new_frame(strng, frame_location, frame_name, frames):
if not(frame_name in frames):
frames[frame_name] = Frame(frame_location)
return frames[frame_name]
With that, you now have a dictionary (frames) that includes a reference for every new frame by name. If you had a frame named "foo", for example, you could configure and pack it like this:
frames["foo"].configure(background="red", ...)
frames["foo"].pack(...)
If preserving the order of the frames is important you can use an OrderedDict.
Related
I have made a LazyRow that i now want to be able to get the scrollposition from. What i understand Scrollablerow has been deprecated. (correct me if im wrong) The thing is that i cant make a scrollablerow so i thought lets make a lazy one then. but i have no clue how to get scrollposition from the lazyrow. i know how to get index but not position if that eaven exists. here is what i have tried.
val scrollState = rememberScrollState()
LazyRow(scrollState = scrollstate){
}
For LazyScrollers, there are separate LazyStates.
I think there's just one, in fact, i.e. rememberLazyListState()
Pass that as the scroll state to the row and then you can access all kinds of info. For example, you could get the index of the first visible item, as well as its offset. There are direct properties for this stuff in the object returned by the above initialisation. You can also perform some more complex operations using the lazyListState.layoutInfo property that you get.
Also, ScrollableRow may be deprecated as a #Composable, but it is just refactored, a bit. Now, you can use the horozontalScroll() and verticalScroll() Modifiers, both of which accept a scrollState parameter, which expects the same object as the one you've created in the question.
Usually, you'd use LazyScrollers since they're not tough to implement and also are super-performant, but the general idea is that they are used with large datasets whereas non-lazy scrollers are okay for small sized lists and stuff. This is because the lazy ones cache only a small fraction of the entire list, making your UI peformant, which is not something regular scrollers do, and not a problem for small datasets.
They're like equivalents of RecyclerView from the View System
I build program, when in one part I have some ranking, and I would like to give users option to customize it.
In my code I have a function that gets objects and returnes them packed with points and position in ranking (for now it calculates the arithmetic mean of some object's values).
My question is is it possible to give e.g. admin chance to write this function via admin panel and use it, so if he would like to one day use harmonic mean he could without changing source code?
Yes, you could just store a string in the database and exec() it with suitable arguments...
However, you'll have to be careful – Python code can practically never be sandboxed perfectly. In the event that you accept any arbitrary Python code for this, and someone with nefarious intents gets to your admin panel to change the expression, they can do practically anything.
In other words, don't use raw Python for the code you store.
Can anyone guide me towards the right direction as to where I should place a script solely for loading data into ndb. As I wish to upload all data into the gae ndb so that the application could perform query on it.
Right now, the loading of data is in my application. I wish to placed it separately from the main application.
Should it be edited in the yaml file?
EDITED
This is a snippet of the entity and the handler to upload the data into GAE ndb.
I wish to placed this chunk of code separately from my main application .py. Reason being the uploading of this data won't be done frequently and to keep the codes in the main application "cleaner".
class TagTrend_refine(ndb.Model):
tag = ndb.StringProperty()
trendData = ndb.BlobProperty(compressed=True)
class MigrateData(webapp2.RequestHandler):
def get(self):
listOfEntities = []
f = open("tagTrend_refine.txt")
lines = f.readlines()
f.close()
for line in lines:
temp = line.strip().split("\t")
data = TagTrend_refine(
tag = temp[0],
trendData = temp[1]
)
listOfEntities.append(data)
ndb.put_multi(listOfEntities)
For example if I placed the above code in a file called dataLoader.py, where should I call this script to invoke?
In app.yaml alongside my main application(knowledgeGraph.application)?
- url: /.*
script: knowledgeGraph.application
You don't show us the application object (no doubt a WSGI app) in your knowledge.py module, so I can't know what URL you want to serve with the MigrateData handler -- I'll just guess it's something like /migratedata.
So the class TagTrend_refine should be in a separate file (usually called models.py) so that both your dataloader.py, and your knowledge.py, can import models to access it (and models.py will need its own import of ndb of course). (Then of course access to the entity class will be as models.TagTrend_refine -- very basic Python).
Next, you'll complete dataloader.py by defining a WSGI app, e.g, at end of file,
app = webapp2.WSGIApplication(routes=[('/migratedata', MigrateData)])
(of course this means this module will need to import webapp2 as well -- can I take for granted a knowledge of super-elementary Python?).
In app.yaml, as the first URL, before that /.*, you'll have:
url: /migratedata
script: dataloader.app
Given all this, when you visit '/migratedata', your handler will read the "tagTrend_refine.txt" file that you uploaded together with your .py, .yaml, and so on, files in your overall GAE application, and unconditionally create one entity per line of that file (assuming you fix the multiple indentation problems in your code as displayed above, but, again, this is just super-elementary Python -- presumably you've used both tabs and spaces and they show up OK in your editor, but not here on SO... I recommend you use strictly, only spaces, never tabs, in Python code).
However this does seem to be a peculiar task. If /migratedata gets visited twice, it will create duplicates of all entities. If you change the tagTrend_refine.txt and deploy a changed variation, then visit /migratedata... all old entities will stick around and all the new entities will join them. And so forth.
Moreover -- /migratedata is NOT idempotent (if visited more than once it does not produce the same state as running it just once) so it shouldn't be a GET (and now we're on to super-elementary HTTP for a change!-) -- it should be a POST.
In fact I suspect (but I'm really flying blind here, since you see fit to give such tiny amounts of information) that you in fact want to upload a .txt file to a POST handler and do the updates that way (perhaps avoiding duplicates...?). However, I'm no mind reader, so this is about as far as I can go.
I believe I have fully answered the question you posted (though perhaps not the one you meant but didn't express:-) and by SO's etiquette it would be nice to upvote and accept this answer, then, if needed, post another question, expressing MUCH more clearly and completely what you're trying to achieve, your current .py and .yaml (ideally with correct indentation), what they actually do and why you'd like to do something different. For POST vs GET in particular, just study When should I use GET or POST method? What's the difference between them? ...
Alex's solution will work, as long as all you data can be loaded in under 1 minute, as that's the timeout for an app engine request.
For larger data, consider calling the datastore API directly from your own computer where you have the source. It's a bit of a hassle because it's a different API; it's not ndb. But it's still a pretty simple API. Here's some code that calls the API:
https://github.com/GoogleCloudPlatform/getting-started-python/blob/master/2-structured-data/bookshelf/model_datastore.py
Again, this code can run anywhere. It doesn't need to be uploaded to app engine to run.
I'm sorry, I'm showing too many lines of code but I just have a small problem.
Take a look at the code file, you'll see two areas which I marked via comment [1] and [2] (Maybe you'll need [3]).
When I run the program, because this is a console program so the screen will have something like:
Befor callback: 0
After callback: 0
It should be After callback: 99 that is what I need.
My question is Why doesn't iResult variable change after I modify it?
Update 1
The 1st agrument of callback function points to where (this) pointer (in [3])points to.
Thank you guys.
When you call run_query to execute your query, it assigned the result of the sqlite3_exec call to iResult. This overwrites the 99 with the result of the query, which is 0.
It's just about everything not optimal about this code. If you're doing something simple, sonsider using an available wrapper, such as hiberlite. There are more low level ones as well.
Try to read about clean code first and about SOLID principles and then about patterns in enterprise software
This is also not what "modern" C++ is good for. Do you really want to do it in C++?
Then, you're doing something dangerous as well - you're assembling a query from a string by not using value binding.
I've narrowed my code down to this-
Function Check-VirtualPhysicalPath{
Param([Parameter(Mandatory=$True)] [AllowEmptyString()][String]$Page)
#This creates an arraylist of items that are our virtual/physical paths
$WebVD= Get-WebVirtualDirectory
}
when I run this script in a function setting the results of 'Get-WebVirtualDirectory' returns a casting error. This has me baffled because when i try to run the line
$WebVD= Get-WebVirtualDirectory
in either a script or merely on the console there are no errors returned and i can access the variable and the data is correct. What am I doing wrong?
Now as a side-note this is merely the problematic code so i'm not including everything, but even when i comment everything else out i end up just running what you see here with problems just the same.
i'm calling the code with this in a separate script
$page = [string]$(gc "C:\page.txt")
. C:\VP.ps1
$(Check-VirtualPhysicalPath($page))
Powershell is reacting like i'm casting the $WebVD variable, I'm not sure if this is a bug or if i'm missing something entirely...
Edit:
it looks like i forgot to pull out that part of the code. I'm code crawling, the point of the hashtable is that i'm storing the number of times a resource is used in a hash table with the key being the file name and the value how many times it has been used so i use regular expressions to determine that. My question is unrelated to my other code because it's having problems even when my code only contains what you see above.