How do you make a breakable loop in Scratch? I'm using Scratch 2.0 and can't find any good way to make a loop breakable, from inside of the loop itself.
Disclaimer:
There is no perfect way to do it. If you can possibly stand this true fact then feel free to continue.
There are a few different ways you could do it.
With repeat until
The first and most simple one follows this:
But this isn't technically part of the script - it's just repeating until some value returns true.
With a custom block (stop this script)
In order to do it inside of the script, you'll need to use a sneaky little trick with custom blocks.
Create a custom block called whatever you want - but probably along the lines of "breakable loop". Inside of it, create this script:
By using stop script we are breaking out of the script that is currently running - which, according to Scratch, is the custom block.
See the result! (as scratchblocks)
With broadcast and wait
You could also use a broadcast-and-wait method, very similar to above:
Though I highly suggest you don't use this method, as if any other sprites have breakable loops you'll need to rename each one, which can be tedious after using a lot of loops in a lot of sprites!
(Note this bug has been fixed in version 442 of the editor and such the following no longer applies.)
Help! My project is lagging a bunch now!
As #foi has noticed, if your code must be run inside of a frame you probably checked run without screen refresh. Unfortunately, due to a bug in the Scratch player, this causes the program to essentially break after the stop this script block has been activated. How can you handle this?
It follows the same principle you use when you use a run without screen refresh custom block inside of a forever loop - the loop doesn't use screen refresh while the inside does, allowing for instant animations whether or not one is using turbo mode.
Here's an example - the image is really too long to be embedded, so see it here instead.
You can make a variable inside or outside of the repeat and make your script like this:
repeat until [[my variable] = [e.g: 1]]
your code
your code
your code
your code
end of repeat until
For a "repeat until" block the simplest way would be to "or" your normal until condition with the break condition in the until.
By adding an incremeting loop counter variable in the loop you can use a "repeat until" to replicate the function of a "repeat n times" block
By using a "repeat until" block with only your break condition you get the equivalent of a "forever" block
If you need another script/ sprite to trigger the break then a public variable will let you break the loop from anywhere and let a single condition break loops for different sprites.
I'd post an image of the blocks but this is my first reply and the site won't let me!
good luck
You can use these few ways to do it...
conditional loop
stop this script
if then else, in the else section, put nothing
I would prefer to use the first method, as it requires less blocks and for the first method, you can still add in code that will be executed after the loop has stopped executing.
You can make it repeat x times or make it have a certain point where it stops, such as another variable changing.
Otherwise, I don't think there is a wat to do that.
Use the repeat until block. Then put in an equals block or whatever into the boolean part. Then inside that repeat until block, put a stop this script block.
Hope this helps :D
Related
I am using this script to close all "Alerts" in my notification bar:
tell application "System Events"
tell process "NotificationCenter"
set numwins to (count windows)
repeat with i from numwins to 1 by -1
click button "Close" of window i
end repeat
end tell
end tell
However this doesn't close them all, even when there are no "Alert without Close button".
try catch didn't help. What's wrong?
I tested your script and it seemed to run correctly on my machine, but there is always a potential for problems when you use a repeat loop on a mutating list: in other words, a list that changes as the repeat loop progresses. Each time you close a window Notification Center changes its window list and updates the properties of the remaining windows; the script can simply lose track. I'm a little surprised it doesn't throw errors when this happens, but...
You can try this code and see if it works. rather than referring to windows by index it repeatedly tries to close the last window, ignoring any errors, and keeps on until the window count is zero or it loops 100 times (that last is to prevent an endless loop in case something goes wrong).
tell application "System Events"
tell process "NotificationCenter"
repeat 100 times
try
tell last window
click button "Close"
end tell
end try
if (count of its windows) = 0 then
exit repeat
end if
end repeat
end tell
end tell
EDIT
Per comments, the above doesn't work quite as advertised, so let's switch it over to AppleScriptObjC:
use framework "Foundation"
property NSUserNotificationCenter : class "NSUserNotificationCenter"
NSUserNotificationCenter's defaultUserNotificationCenter's removeAllDeliveredNotifications()
This seems to do the trick on my machine. Of course, NSUserNotificationCenter is deprecated as of 10.14, so this won't work forever — eventually you'll have to shift over to the notification's framework — but it should work for a few more OS versions.
EDIT 2
Per another comment, anyone working on os 10.14 or later (Mojave and Catalina, to date) can do an equivalent AppleScriptObjC routine using the UserNotifications framework, like so:
use framework "UserNotifications"
set notificationCenter to class "UNUserNotificationCenter"'s currentNotificationCenter
notificationCenter's removeAllDeliveredNotifications()
Note that I've used a slightly different syntax (merely calling class "UNUserNotificationCenter" rather than setting up a property). Both work; the property syntax is only preferable when you need to pass the class to handlers.
I am no longer "new" to Python, but am now moving into unchartered territory.
Recently I was dissecting some logic circuit code found here. I learned a lot about the practical use of inheritance from this code. Good stuff.
Not much happens in this code until one changes the inputs on a gate, so the interpreter must be used to manipulate the inputs. I got tired of using the interpreter, and so I investigated ways to create a continuous loop that would not rerun the initial code.
I found that Tkinter uses a continuous loop that I could then interrupt with the "after" method to update some of the parameters of the code currently running.
That works well, however I am curious as to whether there is another and/or better way. Anyone know of one or the other?
Some of the code:
tk_TkGUI = Tk()
f_AndTest() ## Initialize the 'And' gate
tk_TkGUI.after(1000, f_ChangeAnInput) ## Invokes Tk 'after' method to update an input
tk_TkGUI.mainloop() ## Must be used in Windows with Tkinter
def f_ChangeAnInput():
A1.B.set(0) ## Change A1.B from 1 to 0
If you want a window, using Tkinter in this way is perfectly fine.
By the way, after doesn't interrupt the loop as you described it. The main loop simply loops over a queue of events and processes them in order. When it reaches the end it waits for more events. Much like when you press a key or move the mouse, after merely puts something in the queue to be processed later. It really is as simple as that.
you could use threading.
import thread
def blaH:
#All your code that isn't related to your tkinter stuffs in here
thread.start_new_thread(blaH,())
the only thing is that you need new ways of both threads to talk to each other, such as global variables.
I just started with C, but I had some knowledge of PHP, so I decided to do some 'more complicated' stuff, as for a beginner :)
I used two nested loops to print an 50x50 array. It isn't very slow, but I included a movement with arrow keys to it to move one symbol, X (player) around the array. Every time a move is made, whole array needs to be refreshed, which I did by:
system("cls");
for(x=0;x<50;x++)
{
for(y=0;y<50;y++)
{
printf("%c",table[x][y]);
}
printf("\n");
}
Which is very sloppy solution and whole array 'blinks' while it refreshes after every move.
Is there any more efficient way of doing that in C?
You would probably have to use some sort of shell graphics library like ncurses to move stuff around your array without it blinking when you redraw it. There's not really a simple way to avoid that when you're just using printf to display your grid as output.
I assume you're using Windows (because of the cls).
Maybe ANSI.SYS escape sequences are the simplest way without a library.
You can probably avoid flickering if you move the cursor and overwrite the display contents without clearing the old contents.
There's an example on "Reading and Writing Blocks of Characters and Attributes" with the Win32 Console:
http://msdn.microsoft.com/en-us/library/ms685032%28v=vs.85%29.aspx
Edit: explained the link.
I have web request like this
Loop Controller(3)
moreSamples=true
startIndex=0
While Controller(${__javaScript(${moreSamples}==true)})
SOAP/XML-RPC Request(index=${startIndex})
Regular Expression Extractor(startIndex=newIndex,moreSamples=samples)
Now problem is I am not able to initialize moreSamples and startIndex in loop.
I tried two options:
Make moreSamples and startIndex as user defined variables. Now I am able to change their values using Regular Expression Extractor but not able to reinitialize them in outer loop using BeanShell PostProcessor like this:
vars.put("moreSamples","false")
vars.put("startIndex","0")
Make moreSamples and startIndex as User Parameters in preprocessor of of while loop but then I am not able to assign them values using Regular Expression Extractor.
Please suggest the mistakes or some new construct which can fit in.
Screenshot:
#bpsingh,
Can you do following things:
Add UserDefinedVariables on top of your Test Plan with two defined variables:
moreSamples, startIndex (like #ant suggested already)
Under the Download - PersistentSyncScope Sampler, you have two regular expression extractors in which I assume you want to extract some values and place it in these two variables from the above. Add BeanShellPostProcessor under the Download - PersistentSyncScope Sampler.
In BeanShellPostProcessor add following code:
vars.put("moreSamples","${REGEX_EXTRACT1}");
vars.put("startIndex","${REGEX_EXTRACT2}");
These two (moreSamples, startIndex) are global variables and changes on them should be visible outside of the loop.
Do you have to initialize them from the loop? How about adding those to User Defined Variables?
Or you can do it from your loop as well, the reason why it doesn't work for you is either the fact that you forgot to put the semi-colon ; after your expression(s) :
vars.put("moreSamples","false"); // ; <- was missing
vars.put("startIndex","0"); // ; <- was missing
I used BSF Sampler and it worked for me (don't forget to choose the language -> beanshell if you use this one). Here is my debug sampler (relevant part) :
START.HMS=101818
START.MS=1341821898080
START.YMD=20120709
TESTSTART.MS=1341822195274
moreSamples=false
startIndex=0
Update:
You need not to use both BSF Sampler and user defined variables. You can use either, and I see you have more user defined variables, no need for that. Have one of those at the start of your test. I'm still not clear what your problem is and what you're trying to achieve.
Actually problem here is I am using 2 loops and all answers don't take this properly into account.
Since pre/post processors are applied only to samplers not to loops there is no way to reinitialize the variables before while loop. Thus if I add initialize statements in preprocessor, loop run infinitely and if in postprocessor, it never executes. Only way to initialize is adding BSF sampler before while loop but that will spoil the reports as this sampler will also be recorded by listeners.
So only solution I found is run Download - PersistentSyncScope Sampler once and add BSF preprocessor with following scripts
vars.put("moreSamples","false");
vars.put("startIndex","0");
Now add while loop and add Download - PersistentSyncScope Sampler as its child.
That is the only solution till now. Thanks everyone to help me understand the problem.
I have this code
n_userobject inv_userobject[]
For i = 1 to dw_1.Rowcount()
inv_userobject[i] = create n_userobject
.
.
.
NEXT
dw_1.rowcount() returns only 210 rows. Its so odd that in the range of 170 up, the application stop and crashes on inv_userobject[i] = create n_userobject.
My question, is there any limit on array or userobject declaration using arrays?
I already try destroying it after the loop so as to check if that will be a possible solution, but it is still crashing.
Or how can i be able to somehow refresh the userobject?
Or is there anyone out there encounter this?
Thanks for all your help.
First, your memory problem. You're definitely not running into an array limit. If I was to take a guess, one of the instance variables in n_userobject isn't being cleaned up properly (i.e. pointing to a class that isn't being destroyed when the parent class is destroyed) or pointing to a class that similarly doesn't clean itself up. If you've got PB Enterprise, I'd do a profiling trace with a smaller loop and see what is being garbage collected (there's a utility called CDMatch that really helps this process).
Secondly, let's face it, you're just doing this to avoid writing a reset method. Even if you get this functional, it will never be as efficient as writing your own reset method and reusing the same instance over again. Yes, it's another method you'll have to maintain whenever the instance variable list changes or the defaults change, but you'll easily gain that back in performance.
Good luck,
Terry.
I'm assuming the crash you're facing is at the PBVM level, and not a regular PB exception (which you can catch in your code). If I'm wrong, please add the exception details.
A loop of 170-210 iterations really isn't a large one. However, crashes within loops are usually the result of resource exhaustion. What we usually do in long loops is call GarbageCollect() occasionally. How often should it be called depends on what your code does - using it frequently could allow the use of less memory, but it will slow down the run. Read this for more.
If this doesn't help, make sure the error does not come from some non-PB code (imported DLL or so). You can check the stack trace during the crash to see the exception's origin.
Lastly, if you're supported by Sybase (or a local representative), you can send them a crash dump. They can analyze it, and see if it's a bug in PB, and if so, let you know when it was (or will be) fixed.
What I would normally do with a DataWindow is to create an object that processes the data in a row and call it for each row.
the only suggestion i have for this is to remove the rowcount from the for (For i = 1 to dw_1.Rowcount()) this will cause the code to recount the rows every time it uses one. get the count into a variable and then use the variable. it should run a bit better and be far more easy to debug.