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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...
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
...
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...
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
...
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...
MySQL Conditional Insert
... DBMS does not impose limitations on which table you select from when you execute an insert, try:
INSERT INTO x_table(instance, user, item)
SELECT 919191, 123, 456
FROM dual
WHERE NOT EXISTS (SELECT * FROM x_table
WHERE user = 123
...
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...
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.)
share
|
...
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...