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What's the difference between eval, exec, and compile?
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The short answer, or TL;DR
Basically, eval is used to evaluate a single dynamically generated Python expression, and exec is used to execute dynamically generated Python code only for its side effects.
eval and exec have these two differences:
eval accep...
代码块超过1.2w编译apk报错问题 - App Inventor 2 中文网 - 清泛IT社区，为创新赋能！
...ng.api.ApiProxy$RequestTooLargeException: The request to API call datastore_v3.Put() was too large.
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:416)
at com.google.gwt.user.server.rpc.RPC.invokeAnd...
Removing multiple keys from a dictionary safely
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Why not like this:
entries = ('a', 'b', 'c')
the_dict = {'b': 'foo'}
def entries_to_remove(entries, the_dict):
for key in entries:
if key in the_dict:
del the_dict[key]
A more compact version was provided by mattbornski using dict.pop()
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More elegant way of declaring multiple variables at the same time
...variables with Boolean values is the best way to write your routine (especially if they really have one-letter names :)
Depending on what you're doing, it may make sense to use a dictionary instead. For example, if you want to set up Boolean preset values for a set of one-letter flags, you could d...
Convert a list of data frames into one data frame
I have code that at one place ends up with a list of data frames which I really want to convert to a single big data frame.
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Get item in the list in Scala?
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Use parentheses:
data(2)
But you don't really want to do that with lists very often, since linked lists take time to traverse. If you want to index into a collection, use Vector (immutable) or ArrayBuffer (mutable) or possibly Array (which is just a Java array, exc...
Does Java have something like C#'s ref and out keywords?
...n change internals to the array or object and it will be reflected in the caller.
– Romain Hippeau
May 10 '10 at 21:27
12
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Convert XML to JSON (and back) using Javascript
...cts) and vice versa javascript conversion functions. The library is very small and doesn't require any other additional libraries.
API functions
new X2JS() - to create your instance to access all library functionality. Also you could specify optional configuration options here
X2JS.xml2json - Conve...
How to declare a global variable in php?
...'];
}
From the Manual:
An associative array containing references to all variables which are currently defined in the global scope of the script. The variable names are the keys of the array.
If you have a set of functions that need some common variables, a class with properties may be a g...
CSS styling in Django forms
...ling, if you need an unique identifier its better to use id. Second its usually the template side's responsobilty to do exaclty this, Esspecially if you are going to access this class via frontend methods (js, css). I didn't say your answer is wrong. In my opinion its just bad practice (esspecially ...