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Passing a 2D array to a C++ function
...
Fixed Size
1. Pass by reference
template <size_t rows, size_t cols>
void process_2d_array_template(int (&array)[rows][cols])
{
std::cout << __func__ << std::endl;
for (size_t i = 0; i < rows; ++i)
{
std::cout << i << ...
When should iteritems() be used instead of items()?
... more like a set (which you'd expect from a dict).
Simple example:
common_keys = list(dict_a.viewkeys() & dict_b.viewkeys())
Will give you a list of the common keys, but again, in Python 3.x - just use .keys() instead.
Python 3.x has generally been made to be more "lazy" - i.e. map is now e...
Creating Threads in python
...see how:
from threading import Thread
from time import sleep
def threaded_function(arg):
for i in range(arg):
print("running")
sleep(1)
if __name__ == "__main__":
thread = Thread(target = threaded_function, args = (10, ))
thread.start()
thread.join()
print("th...
Placeholder in UITextView
...uble.
UIPlaceHolderTextView.h:
#import <Foundation/Foundation.h>
IB_DESIGNABLE
@interface UIPlaceHolderTextView : UITextView
@property (nonatomic, retain) IBInspectable NSString *placeholder;
@property (nonatomic, retain) IBInspectable UIColor *placeholderColor;
-(void)textChanged:(NSNotif...
MQTT客户端内置版使用指导 · App Inventor 2 中文网
...入口。
案例一：连接并订阅
when 按钮_连接.Click() {
MqttClient1.Connect(true)
}
when MqttClient1.ConnectionStateChanged(新状态, 状态文本) {
标签1.Text = 状态文本
if MqttClient1.IsConnected {
MqttClient1.Subscribe("demo/status", 0)
}
}
...
Is there a standard way to list names of Python modules in a package?
...tforward way to list the names of all modules in a package, without using __all__ ?
10 Answers
...
Parse JSON String into a Particular Object Prototype in JavaScript
...ant to. That's all I'm sayin'. I was really looking for the one-liner: x.__proto__ = X.prototype; (although it's not IE browser compatible at this time)
– BMiner
May 3 '11 at 18:56
...
Weighted random numbers
...er is less than that item's weight
Pseudo-code illustrating this:
int sum_of_weight = 0;
for(int i=0; i<num_choices; i++) {
sum_of_weight += choice_weight[i];
}
int rnd = random(sum_of_weight);
for(int i=0; i<num_choices; i++) {
if(rnd < choice_weight[i])
return i;
rnd -= choic...
Why doesn't list have safe “get” method like dictionary?
...f your list).
Of course, you can easily implement this yourself:
def safe_list_get (l, idx, default):
try:
return l[idx]
except IndexError:
return default
You could even monkeypatch it onto the __builtins__.list constructor in __main__, but that would be a less pervasive change since...
Why is it slower to iterate over a small string than a small list?
...sions. I'll examine the compiled code.
For Python 3:
import dis
def list_iterate():
[item for item in ["a", "b", "c"]]
dis.dis(list_iterate)
#>>> 4 0 LOAD_CONST 1 (<code object <listcomp> at 0x7f4d06b118a0, file "", line 4>)
#>>> ...