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Compare two DataFrames and output their differences side-by-side
...original question
The first step is to concatenate the DataFrames horizontally with the concat function and distinguish each frame with the keys parameter:
df_all = pd.concat([df.set_index('id'), df2.set_index('id')],
axis='columns', keys=['First', 'Second'])
df_all
It's pr...
What's the meaning of interface{}?
...interface that has no methods.
Since there is no implements keyword, all types implement at least zero methods, and satisfying an interface is done automatically, all types satisfy the empty interface.
That means that if you write a function that takes an interface{} value as a parameter, yo...
What happens to a detached thread when main() exits?
..._local) variables of other threads nor static objects.
This appears to be allowed to allow thread managers as static objects (note in [basic.start.term]/4 says as much, thanks to @dyp for the pointer).
Problems arise when the destruction of static objects has finished, because then execution enter...
Non-alphanumeric list order from os.listdir()
...however you want. Based on what you describe,
sorted(os.listdir(whatever_directory))
Alternatively, you can use the .sort method of a list:
lst = os.listdir(whatever_directory)
lst.sort()
I think should do the trick.
Note that the order that os.listdir gets the filenames is probably complet...
Force to open “Save As…” popup open at text link click for PDF in HTML
... the time of this comment, I've tested it on Chrome, Opera, Edge, Mozilla. All latest. Is working on all except on Mozilla.
– S.I.
Sep 29 '17 at 5:07
7
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Python - 'ascii' codec can't decode byte
I'm really confused. I tried to encode but the error said can't decode... .
7 Answers
...
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
};...
Dictionaries and default values
...collections import defaultdict
a = defaultdict(lambda: "default", key="some_value")
a["blabla"] => "default"
a["key"] => "some_value"
You can pass any ordinary function instead of lambda:
from collections import defaultdict
def a():
return 4
b = defaultdict(a, key="some_value")
b['absent...
How to dump a dict to a json file?
...
you can supply all those parameters to dump(sample, file, ...) too. The extra step of writing to a string is not needed. dump internally writes in chunks. This could be more efficient than to compile a (possibly huge) string first.
...
What is the purpose of “return await” in C#?
...n async method behave differently: when combined with using (or, more generally, any return await in a try block).
Consider these two versions of a method:
Task<SomeResult> DoSomethingAsync()
{
using (var foo = new Foo())
{
return foo.DoAnotherThingAsync();
}
}
async Tas...