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How to set a Django model field's default value to a function call / callable (e.g., a date relative
... to create a field in the class.
PRE Django 1.7
Django lets you pass a callable as the default, and it will invoke it each time, just as you want:
from datetime import datetime, timedelta
class MyModel(models.Model):
# default to 1 day from now
my_date = models.DateTimeField(default=lambda: ...
How to convert string to boolean php
...ted by @lauthiamkok in the comments. I'm posting it here as an answer to call more attention to it.
Depending on your needs, you should consider using filter_var() with the FILTER_VALIDATE_BOOLEAN flag.
filter_var( true, FILTER_VALIDATE_BOOLEAN); // true
filter_var( 'true', FILTER_VALIDATE_...
How to throw std::exceptions with variable messages?
...atter & operator << (const Type & value)
{
stream_ << value;
return *this;
}
std::string str() const { return stream_.str(); }
operator std::string () const { return stream_.str(); }
enum ConvertToString
{
to_str
};...
How to test android referral tracking?
...ust run in a terminal:
adb shell
am broadcast -a com.android.vending.INSTALL_REFERRER -n <your.package>/.<path.up.until.your.BroadcastReceiver> --es "referrer" "utm_source=test_source\&utm_medium=test_medium\&utm_term=test_term\&utm_content=test_content\&utm_campaign=te...
Migration: Cannot add foreign key constraint
...signed();
$table->string('priority_name');
$table->smallInteger('rank');
$table->text('class');
$table->timestamps('timecreated');
});
Schema::table('priorities', function($table) {
$table->foreign('user_id')->references('id')->on('...
Error 1022 - Can't write; duplicate key in table
...ou can not have the same foreign key names in the database tables.
Check all your tables and all your foreign keys and avoid having two foreign keys with the same exact name.
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How should I print types like off_t and size_t?
...6, some_uint16_t);
They are listed in the manpage of inttypes.h.
Personally, I would just cast the values to unsigned long or long like another answer recommends. If you use C99, then you can (and should, of course) cast to unsigned long long or long long and use the %llu or %lld formats respect...
How to POST JSON Data With PHP cURL?
...re indicating Content-Type:application/json, but you are not json-encoding all of the POST data -- only the value of the "customer" POST field. Instead, do something like this:
$ch = curl_init( $url );
# Setup request to send json via POST.
$payload = json_encode( array( "customer"=> $data ) );...
Get difference between two lists
...hat this only returns the temp1-temp2? .. As other said in order to return all the differences you have to use the sysmetric difference: list(set(temp1) ^ set(temp2))
– rkachach
Feb 16 '16 at 16:00
...
Thread-safe List property
...
ConcurrentBag doesn't implement IList and is not actually thread safe version of List
– Vasyl Zvarydchuk
Apr 3 '17 at 20:55
...