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Can I make the foreign key field optional in Django model
...ent because typically if you're going to allow a field to be blank in your form, you're going to also need your database to allow NULL values for that field. The exception is CharFields and TextFields, which in Django are never saved as NULL. Blank values are stored in the DB as an empty string (''...
What's the difference between eval, exec, and compile?
...UE <- return top of stack
'single' is a limited form of 'exec' which accepts a source code containing a single statement (or multiple statements separated by ;) if the last statement is an expression statement, the resulting bytecode also prints the repr of the value of th...
How to check if a string is a valid date
... real life as you force the caller to check for nil, eg. particularly when formatting. If you return a default date|error it may be friendlier.
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iPad keyboard will not dismiss if modal ViewController presentation style is UIModalPresentationForm
...r reasoning is that the user is often going to be entering data in a modal form so they are trying to be "helpful" and keep the keyboard visible where ordinarily various transitions within the modal view can cause the keyboard to show/hide repeatedly.
edit: here is the response of an Apple engineer...
Convert Data URI to File then append to FormData
...k is to extract an image file from the canvas object and append it to a FormData object for upload.
14 Answers
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Run command on the Ansible host
... work with command? Because as far as I know we cannot use the param free_form to define the command that will be executed
– Ander
Sep 8 '16 at 4:40
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Preview an image before it is uploaded
...ogleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form runat="server">
<input type='file' id="imgInp" />
<img id="blah" src="#" alt="your image" />
</form>
Also, you can try this sample here.
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The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value
...yChanges with a model object that has only been populated with data in the form (headline, story, and image). ApplyPropertyChanges applies changes to all properties of the object, including your uninitialized DateTime, which is set to 0001-01-01, which is outside of the range of SQL Server's DATETI...
Cloning a private Github repo
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Private clone URLs take the form git@github.com:username/repo.git - perhaps you needed to use git@ rather than git://?
git:// URLs are read only, and it looks like private repos do not allow this form of access.
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Swift: Testing optionals for nil
... // Do something using `xyz`.
}
This produces an error:
does not conform to protocol 'BooleanType.Protocol'
You have to use one of these forms:
if xyz != nil {
// Do something using `xyz`.
}
if let xy = xyz {
// Do something using `xy`.
}
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