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Why is the order in dictionaries and sets arbitrary?
... was written before the implementation of the dict type changed, in Python 3.6. Most of the implementation details in this answer still apply, but the listing order of keys in dictionaries is no longer determined by hash values. The set implementation remains unchanged.
The order is not arbitrary,...
Finding median of list in Python
...
Python 3.4 has statistics.median:
Return the median (middle value) of numeric data.
When the number of data points is odd, return the middle data point.
When the number of data points is even, the median is interpolated b...
How to assert two list contain the same elements in Python? [duplicate]
...
163
As of Python 3.2 unittest.TestCase.assertItemsEqual(doc) has been replaced by unittest.TestCase....
How to swap keys and values in a hash
... (in essence, by letting you access keys through values):
{a: 1, b: 2, c: 3}.key(1)
=> :a
If you want to keep the inverted hash, then Hash#invert should work for most situations:
{a: 1, b: 2, c: 3}.invert
=> {1=>:a, 2=>:b, 3=>:c}
BUT...
If you have duplicate values, invert will...
How do I override nested NPM dependency versions?
...
243
You can use npm shrinkwrap functionality, in order to override any dependency or sub-dependency....
Bundler: Command not found
I am hosting on a vps, ubuntu 10.04, rails 3, ruby and mysql installed correctly by following some tutorials. If I run bundle check or bundle install I get the error '-bash: bundle: command not found'. From gem list --local I see 'bundler (1.0.2, 1.0.0)' is installed.
...
Replace values in list using Python [duplicate]
...n-place if you want, but it doesn't actually save time:
items = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
for index, item in enumerate(items):
if not (item % 2):
items[index] = None
Here are (Python 3.6.3) timings demonstrating the non-timesave:
In [1]: %%timeit
...: items = [0, 1, 2, 3,...
石头剪刀布 · App Inventor 2 中文网
...
标签_矩阵第1行 标签_矩阵第2行 标签_矩阵第3行
标签
显示那张”学习表”
按钮_重置
按钮
清零重来
素材是三张手势图，工程里已经上传好了：
机器是怎么“学”的：转移...
App Inventor 2 数据可视化教程 - 折线图/曲线图/实时数据绘图 · App Inventor 2 中文网
...图表类型
三、快速上手：第一个折线图
3.1 界面设计
3.2 积木块：添加静态数据
3.3 用 CSV 方式一次性导入数据
四、实时数据绘图（动态折线图）
4.1 使用计时器定时添加数据
4.2 保持图...
pandas GroupBy columns with NaN (missing) values
...
138
This is mentioned in the Missing Data section of the docs:
NA groups in GroupBy are automatica...