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sqlalchemy: how to join several tables by one query?
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A good style would be to setup some relations and a primary key for permissions (actually, usually it is good style to setup integer primary keys for everything, but whatever):
class User(Base):
__tablename__ = 'users'
email = Column(String, primary_key=True)
name = Column(St...
Transpose/Unzip Function (inverse of zip)?
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notice: you can meet memory and performance issues with very long lists.
– Laurent LAPORTE
Oct 14 '16 at 12:44
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When should I use nil and NULL in Objective-C?
...ith an object.
if(str==nil)
NSLog("str is empty");
Now NULL is used for non-object pointer (like a C pointer) in Objective-C. Like nil , NULL got no value nor address.
char *myChar = NULL;
struct MyStruct *dStruct = NULL;
So if there is a situation, when I need to check my struct (structur...
Greenlet Vs. Threads
... in userspace, and that's typically CPU-heavy stuff. Concurrency is useful for breaking apart problems, enabling different parts to be scheduled and managed more easily in parallel.
Greenlets really shine in network programming where interactions with one socket can occur independently of interacti...
Why can't I use a list as a dict key in python?
I'm a bit confused about what can/can't be used as a key for a python dict.
11 Answers
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JavaScript pattern for multiple constructors
I need different constructors for my instances. What is a common pattern for that?
9 Answers
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What to put in a python module docstring? [closed]
... I've read both PEP 8 and PEP 257 , and I've written lots of docstrings for functions and classes, but I'm a little unsure about what should go in a module docstring. I figured, at a minimum, it should document the functions and classes that the module exports, but I've also seen a few modules t...
Extract substring in Bash
Given a filename in the form someletters_12345_moreleters.ext , I want to extract the 5 digits and put them into a variable.
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Python: Bind an Unbound Method?
...t to have calls to magic functions in my code (i.e. __get__). I don't know for which version of python this you tested this on, but on python 3.4, the MethodType function takes two arguments. The function and the instance. So this should be changed to types.MethodType(f, C()).
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What is the difference between join and merge in Pandas?
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pandas.merge() is the underlying function used for all merge/join behavior.
DataFrames provide the pandas.DataFrame.merge() and pandas.DataFrame.join() methods as a convenient way to access the capabilities of pandas.merge(). For example, df1.merge(right=df2, ...) is eq...