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How do I use arrays in C++?
...t of an array, there is no way to detect how large that array is or where exactly the pointer points to relative to the bounds of the array. Pointers are extremely stupid.
Arrays are not pointers
The compiler will silently generate a pointer to the first element of an array whenever it is deemed u...
What does -> mean in Python function definitions?
...
It's a function annotation.
In more detail, Python 2.x has docstrings, which allow you to attach a metadata string to various types of object. This is amazingly handy, so Python 3 extends the feature by allowing you to attach metadata to functions describing their parameters an...
I want to get the type of a variable at runtime
...ble" is always present, and can be passed around as a type parameter. For example:
val x = 5
def f[T](v: T) = v
f(x) // T is Int, the type of x
But depending on what you want to do, that won't help you. For instance, may want not to know what is the type of the variable, but to know if the type o...
Use of 'prototype' vs. 'this' in JavaScript?
...
The examples have very different outcomes.
Before looking at the differences, the following should be noted:
A constructor's prototype provides a way to share methods and values among instances via the instance's private [[Prot...
Split column at delimiter in data frame [duplicate]
... split one column into two within at data frame based on a delimiter. For example,
6 Answers
...
How to check whether a variable is a class or not?
... inspect.isclass function.
>>> import inspect
>>> class X(object):
... pass
...
>>> inspect.isclass(X)
True
>>> x = X()
>>> isinstance(x, X)
True
>>> y = 25
>>> isinstance(y, X)
False
...
What part of Hindley-Milner do you not understand?
...orizontal bar means that "[above] implies [below]".
If there are multiple expressions in [above], then consider them anded together; all of the [above] must be true in order to guarantee the [below].
: means has type
∈ means is in. (Likewise ∉ means "is not in".)
Γ is usually used to refer to a...
Normalize data in pandas
...0.932785 4.535396 0.598124
In [93]: df_norm = (df - df.mean()) / (df.max() - df.min())
In [94]: df_norm
Out[94]:
a b c d
A 0.085789 -0.394348 0.337016 -0.109935
B -0.463830 0.164926 -0.650963 0.256714
C -0.158129 0.605652 -0.035090 -0.573389
D 0.536170 -0...
STL 算法 - C/C++ - 清泛网 - 专注C/C++及内核技术
...mplate<class InIt1, class InIt2> bool equal(InIt1 first, InIt1 last, InIt2 x);
template<class InIt1, class InIt2, class Pred> bool equal(InIt1 first, InIt1 last, InIt2 x, Pred pr);
includes
<algorithm>
判断第一个指定范围内的所有元素是否都被第二个范围包含...
Convert Dictionary to semicolon separated string in c#
...
using System.Linq;
string s = string.Join(";", myDict.Select(x => x.Key + "=" + x.Value).ToArray());
(And if you're using .NET 4, or newer, then you can omit the final ToArray call.)
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