Derek Zeng

Loneliness is the gift of life

Python built-in tools that you must know

This is a study note about Python basics. (based on python 3.6) itertools Helper functions returns iterator. import itertools as it Infinite sequence count, cycle, repeat c = it.count(10) print...

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Vue 2.0 - 2 way data binding more in-depth analysis

This is a review on https://github.com/DDFE/DDFE-blog/issues/7 based on vue 2.0. (Courtesy of https://vuejs.org) In the original article, the author did talk about different participants of 2 way ...

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Angular, Redux, ngrx and complexity management

Having a proper way to manage complexity is crucially important in software development. It leads an established way of adding featurs and fixing bugs, so the software can grow as big as you wish ...

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Angular data model and Redux

We know that Angular uses component based architecture. Each component is an independent piece of UI that consists of its own state management, styles and templates. A component can be composed o...

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Play with Reactive programming (1)

Rxjs is a popular library now. I used it when working on my Radio Player project. The Angular uses it as a way to pass data between components. Because the data passed can be async and continuous, ...

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Top command is actaully pretty useful

After I switched to ubuntu, I discovered quite a few useful commandline utilities. Top is one of them that I underestimated for a long time. In the past, whenever I want to check system resource us...

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我平时喜欢听电台广播。以前在新加坡上中学住宿舍的时候我就买了一个大家伙,它可以放广播,也可以放CD。 学习之余都是这个家伙陪伴着我。我最喜欢的电台是Yes 93.3,新加坡最受年轻人欢迎的音乐电台。经常可以听到 我喜欢的港台新歌手比如梁静茹,林俊杰的歌。这么多年过去了,它的风格没有太大变化。对于我来说这是好事情, 毕竟现在的新歌(手)都不如老歌(手)。 离开新加坡好几年了,时不时还会在网络上...

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Segment tree and Binary indexed tree (2)

Binary indexed tree (BIT) is an interesting data structure. It makes calculating and updating prefix sum efficient. In the old way of keeping prefix sum, you have to keep an accumulative array c[]....

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Segment tree and Binary indexed tree (1)

Recently, I discovered two interesting data structures, Segment tree and Binary index tree (BIT). Both data structures are good at managing some range of aggregated values. For example, in a discre...

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How to design a proper permission system

Any content management system must have a robust "auth" component. "Auth" stands for authentication and authorization. Authentication is an well talked topic. Authorization is the interest of this ...

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