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How to “perfectly” override a dict?
...or other builtins) directly. It often makes no sense, because what you actually want to do is implement the interface of a dict. And that is exactly what ABCs are for.
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Calling a function of a module by using its name (a string)
What is the best way to go about calling a function given a string with the function's name in a Python program. For example, let's say that I have a module foo , and I have a string whose content is "bar" . What is the best way to call foo.bar() ?
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Manually put files to Android emulator SD card
...o push any file or folder to the mnt/sdcard dir, I had to use storage/12EA-2A1E instead. Probably that folder name is auto-generated for each AVD.
– gosr
Oct 1 '17 at 13:40
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What does Expression.Quote() do that Expression.Constant() can’t already do?
...pression.Add(ps, pt),
pt)),
ps);
var f2a = (Func<int, Expression<Func<int, int>>>)ex2.Compile();
var f2b = f2a(200).Compile();
Console.WriteLine(f2b(123));
And indeed, if you compile and run this code you get the right answer.
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private[this] vs private
...rotected over public doesn't apply.
Use private[this] where performance really matters (since you'll get direct field access instead of methods this way). Otherwise, just settle on one style so people don't need to figure out why this property is private and that one is private[this].
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Why aren't python nested functions called closures?
...s in Python, and they match the definition of a closure. So why are they called nested functions instead of closures ?
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What is a “callable”?
...t's clear what a metaclass is , there is an associated concept that I use all the time without knowing what it really means.
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Split data frame string column into multiple columns
...ry(tidyr)
before <- data.frame(
attr = c(1, 30 ,4 ,6 ),
type = c('foo_and_bar', 'foo_and_bar_2')
)
before %>%
separate(type, c("foo", "bar"), "_and_")
## attr foo bar
## 1 1 foo bar
## 2 30 foo bar_2
## 3 4 foo bar
## 4 6 foo bar_2
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Iterate over the lines of a string
...())'
10000 loops, best of 3: 61.5 usec per loop
Note we need the list() call to ensure the iterators are traversed, not just built.
IOW, the naive implementation is so much faster it isn't even funny: 6 times faster than my attempt with find calls, which in turn is 4 times faster than a lower-lev...
Efficiently updating database using SQLAlchemy ORM
...ngs in mind when using the ORM and plain SQL in the same transaction. Basically, from one side, ORM data modifications will only hit the database when you flush the changes from your session. From the other side, SQL data manipulation statements don't affect the objects that are in your session.
So...