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What is the difference between Ruby 1.8 and Ruby 1.9
..."cat"[1]
=> 97
{"a","b"} No Longer Supported
Ruby 1.9
irb(main):002:0> {1,2}
SyntaxError: (irb):2: syntax error, unexpected ',', expecting tASSOC
Ruby 1.8.6
irb(main):001:0> {1,2}
=> {1=>2}
Action: Convert to {1 => 2}
Array.to_s Now Contains Punctuation
Ruby 1.9
irb...
App Inventor 2 低功耗蓝牙(BLE) 硬件接入、数据通信及IO控制 - App Invent...
...为通用、价格低廉的BLE设备从零开始如何利用App Inventor 2开发一款自己专属的手机蓝牙App应用。BLE与经典蓝牙的区别可参考：《低功耗蓝牙(BLE) 和 经典蓝牙(SPP) 的区别》。本文主要通过一款常见的BLE硬件接入控制，介绍硬件接入...
What's the difference between equal?, eql?, ===, and ==?
...
+200
I'm going to heavily quote the Object documentation here, because I think it has some great explanations. I encourage you to read it...
How can I force division to be floating point? Division keeps rounding down to 0?
...
In Python 2, division of two ints produces an int. In Python 3, it produces a float. We can get the new behaviour by importing from __future__.
>>> from __future__ import division
>>> a = 4
>>> b = 6
>>...
Sorting 1 million 8-decimal-digit numbers with 1 MB of RAM
...
1
2
Next
720
...
Java code To convert byte to Hexadecimal
...
byte[] bytes = {-1, 0, 1, 2, 3 };
StringBuilder sb = new StringBuilder();
for (byte b : bytes) {
sb.append(String.format("%02X ", b));
}
System.out.println(sb.toString());
// prints "FF 00 01 02 03 "
See also
java.util....
Are tuples more efficient than lists in Python?
... is much faster than assigning a list.
>>> def a():
... x=[1,2,3,4,5]
... y=x[2]
...
>>> def b():
... x=(1,2,3,4,5)
... y=x[2]
...
>>> import dis
>>> dis.dis(a)
2 0 LOAD_CONST 1 (1)
3 LOAD_CONST ...
Redirect stderr and stdout in Bash
...
792
Take a look here. Should be:
yourcommand &>filename
(redirects both stdout and stderr ...
Splitting a list into N parts of approximately equal length
... equal parts? For example, if the list has 7 elements and is split it into 2 parts, we want to get 3 elements in one part, and the other should have 4 elements.
...
Import error: No module name urllib2
...
As stated in the urllib2 documentation:
The urllib2 module has been split across several modules in Python 3 named urllib.request and urllib.error. The 2to3 tool will automatically adapt imports when converting your sources to Python 3.
So yo...