generator

MyBatis Generator介绍目录

放肆的年华 提交于 2020-04-06 19:54:52
1. MyBatis Generator介绍 2. MyBatis Generator新增功能 3. MyBatis Generator 快速入门指南 4. 运行 MyBatis Generator 5. 运行 MyBatis Generator 后的任务 6. Migrating from Ibator 7. Migrating from Abator 8. MyBatis Generator XML 配置参考 9. 使用生成的对象 10. 使用注意事项 11. 参考资料 来源: oschina 链接: https://my.oschina.net/u/1024408/blog/490699

Python `yield from`, or return a generator?

心不动则不痛 提交于 2020-04-05 08:40:47
问题 I wrote this simple piece of code: def mymap(func, *seq): return (func(*args) for args in zip(*seq)) Should I use the 'return' statement as above to return a generator, or use a 'yield from' instruction like this: def mymap(func, *seq): yield from (func(*args) for args in zip(*seq)) and beyond the technical difference between 'return' and 'yield from', which is the better approach the in general case? 回答1: The difference is that your first mymap is just a usual function, in this case a

Create Pandas Dataframe from List of Generators

只愿长相守 提交于 2020-03-26 15:13:21
问题 I have to following question. Is there a way to build a DataFrame from a list of python Generator objects. I used list comprehension to create the list with data for the dataframe: data_list.append([record.Timestamp,record.Value, record.Name, record.desc] for record in records) I did it this way because normal list append in a for loop is taking like 20x times longer: for record in records: data_list.append(record.Timestamp,record.Value, record.Name, record.desc) I tried to create the

Create Pandas Dataframe from List of Generators

我的梦境 提交于 2020-03-26 15:11:47
问题 I have to following question. Is there a way to build a DataFrame from a list of python Generator objects. I used list comprehension to create the list with data for the dataframe: data_list.append([record.Timestamp,record.Value, record.Name, record.desc] for record in records) I did it this way because normal list append in a for loop is taking like 20x times longer: for record in records: data_list.append(record.Timestamp,record.Value, record.Name, record.desc) I tried to create the

How to return a generator using joblib.Parallel()?

吃可爱长大的小学妹 提交于 2020-03-21 10:47:07
问题 I have a piece of code below where the joblib.Parallel() returns a list. import numpy as np from joblib import Parallel, delayed lst = [[0.0, 1, 2], [3, 4, 5], [6, 7, 8]] arr = np.array(lst) w, v = np.linalg.eigh(arr) def proj_func(i): return np.dot(v[:,i].reshape(-1, 1), v[:,i].reshape(1, -1)) proj = Parallel(n_jobs=-1)(delayed(proj_func)(i) for i in range(len(w))) Instead of a list, how do I return a generator using joblib.Parallel() ? Edit: I have updated the code as suggested by

ES6 Generator 初体验

孤街浪徒 提交于 2020-03-21 04:17:01
3 月,跳不动了?>>> ES6 Generator 初体验 听说 ES6 的 Generator 是一个很神奇的函数,所以去了解了一下。 因为它不同于以往的寻常函数,但是带来的体验却非常好 。这里首先讲了 Generator 是什么,分割线后面用了一个例子来说明 Generator 到底好在哪里 ~ (可以选择性阅读~ ) Generator 是一种异步编程解决方案,不明白?往下看 ~ Generator 到底是什么?官方文档是这样说的:“Generators are functions which can be exited and later re-entered. Their context (variable bindings) will be saved across re-entrances.” 意思就是 Generator 函数内部的执行是可以暂停的。你能够执行到一半退出函数,同时执行到当前的上下文环境(包括变量等等)全部被保存下来,如果我们稍后又进来继续执行下一段,此时是在上次状态的基础上继续往下执行。感觉和别的函数很不一样,如何去理解呢? 直接上代码: var myGen = function*(){ // 定义一个 Generator 函数 var one = yield 1; var two = yield 2; var three = yield 3;

notes on python

十年热恋 提交于 2020-03-05 23:12:53
iterator Behind the scenes, the for statement calls iter( ) on the container object. The function returns an iterator object that defines the method __next__() which accesses elements in the container one at a time. When there are no more elements, __next__() raises a StopIteration exception which tells the for loop to terminate.You can call the __next__() method using the next() built-in function 可以自己实现一个类的for loop: class A: class it: def __init__(s,a): s.a=a s.l=len(s.a.l)+len(s.a.l2) s.i=0 def __next__(s): if s.i==s.l: raise StopIteration a=0 if s.i<len(s.a.l): a= s.a.l[s.i] else: a= s.a.l2

npm ERR! tar.unpack untar error keep showing

倖福魔咒の 提交于 2020-03-05 10:43:09
问题 this error comes not only generator-angular, but also any other generators.. vmware + ubuntu14 + nvm I installed gulp package, and adjust my $PATH. also tried 'npm cache clean' BUT nothing works for me.. somehow I made good one but never made again.. 回答1: I had problems with this when using npm on a ubuntu 14 instance running using virtualbox. From what I remember I think it has to do with the repository sources Try installing node using these instructions. https://github.com/joyent/node/wiki

Joining two DirectoryIterators in Keras

江枫思渺然 提交于 2020-03-05 08:12:49
问题 Suppose I have something like the following: image_data_generator = ImageDataGenerator(rescale=1./255) train_generator = image_data_generator.flow_from_directory( 'my_directory', target_size=(28, 28), batch_size=32, class_mode='categorical' ) Then my train_generator is filled with data from my_directory , which contains two subfolders which separate the data into classes 0 and 1 . Suppose also I have another directory that_directory , also with data split into classes 0 and 1 . I want to

Joining two DirectoryIterators in Keras

感情迁移 提交于 2020-03-05 08:12:32
问题 Suppose I have something like the following: image_data_generator = ImageDataGenerator(rescale=1./255) train_generator = image_data_generator.flow_from_directory( 'my_directory', target_size=(28, 28), batch_size=32, class_mode='categorical' ) Then my train_generator is filled with data from my_directory , which contains two subfolders which separate the data into classes 0 and 1 . Suppose also I have another directory that_directory , also with data split into classes 0 and 1 . I want to