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Reference — What does this symbol mean in PHP?
... have the same results.
Pre-increment is a little bit faster because it really increments the variable and after that 'returns' the result. Post-increment creates a special variable, copies there the value of the first variable and only after the first variable is used, replaces its value with seco...
Unique BooleanField value in Django?
... save method of the model and if you've set the boolean to True, make sure all others are set to False.
from django.db import transaction
class Character(models.Model):
name = models.CharField(max_length=255)
is_the_chosen_one = models.BooleanField()
def save(self, *args, **kwargs):
...
Creating a new column based on if-elif-else condition
I have a DataFrame df :
4 Answers
4
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How does the vim “write with sudo” trick work?
Many of you have probably seen the command that allows you to write on a file that needs root permission, even when you forgot to open vim with sudo:
...
Convert generic List/Enumerable to DataTable?
I have few methods that returns different Generic Lists.
27 Answers
27
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In which situations do we need to write the __autoreleasing ownership qualifier under ARC?
...ents that are passed by reference (id *) and are autoreleased on return.
All of this is very well explained in the ARC transition guide.
In your NSError example, the declaration means __strong, implicitly:
NSError * e = nil;
Will be transformed to:
NSError * __strong error = nil;
When you c...
How to compare two files not in repo using git
I'd like to compare two css files which are not in any git repository. Is there such a functionality in git?
3 Answers
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How to pick just one item from a generator?
... would use the second syntax given in my answer, next(g). This will internally call g.__next__(), but you don't really have to worry about that, just as you usually don't care that len(a) internally calls a.__len__().
– Sven Marnach
Apr 10 '14 at 10:31
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How to know if an object has an attribute in Python
...n is that, if the property is likely to be there most of the time, simply call it and either let the exception propagate, or trap it with a try/except block. This will likely be faster than hasattr. If the property is likely to not be there most of the time, or you're not sure, using hasattr will pr...
Android SDK Manager Not Installing Components
Not sure what I'm doing wrong here. I installed the Android SDK Manager, and am now trying to install a platform like the Android Dev website suggests. Once I clicked install I got an error stating that the Manager could not create a temp folder within the Android directory. So I created it. Now I'm...