How to sort a list in Python
## 1. Object oriented way: ```python list = [4,3,2,1] list.sort() # => return nothing list # => [1,2,3,4] ``` - called from object ...
Finally we have multi env credential in Rails 6
In Rails 6, default credential is for development and staging, they'll store in the same path ``` config/credentials.yml.enc config/mast...
When to use Hash and when to use HashWithIndifferentAccess and why
## TL;DR: * When passing to our class: Both works, because we control everything * When passing to 3rd party library: Hash is better, we...
Keyword argument in Ruby 3
https://blog.saeloun.com/2019/10/07/ruby-2-7-keyword-arguments-redesign.html
Can't find custom headers in Axios response
It's CORS issue, configure CORS setting for browser will fix this. https://stackoverflow.com/questions/37897523/axios-get-access-to-resp...
複習一下各種排序法，和 Python 實現
搭配題目和講解影片服用： * Lintcode: https://www.lintcode.com/problem/sort-integers * Leetcode: https://leetcode.com/problems/sort-an-array/ * https...
Remove Duplicate Numbers in Array
## Question https://www.lintcode.com/problem/remove-duplicate-numbers-in-array/description https://leetcode.com/problems/remove-duplicat...
Classical Binary Search - recursion version
## Question: 457. Classical Binary Search Find any position of a target number in a sorted array. Return -1 if target does not exist. ...
什么是拓扑排序（Topological Sorting）
直接 copy 過來： 一、什么是拓扑排序 在图论中，拓扑排序（Topological Sorting）是一个有向无环图（DAG, Directed Acyclic Graph）的所有顶点的线性序列。且该序列必须满足下面两个条件： 每个顶点出现且只出现一次。 若存在一...
Python deque 用法
1. deque 類似於 list (ruby 的 array)，只不過 deque 可以操作兩端 2. deque 是 tread safe，所以可以同時操作 何謂操作兩端？這個 example 看一下即了解： ```py import collections d1...
Graph theory basic - Set and adjacency list
：陣列讀取 * O(n)：簡易搜尋 * O(log n)：二分搜尋 * O(nlogn)：合併排序 * O(n²)：選擇排序 * O(2^n)：費波那契數列 時間複雜度為 O(n) ...
Start using Stripe's PaymentIntent instead of Charge to fit SCA
Since a new rule coming into effect on September 14, 2019, as part of PSD2 regulation in Europe, any integrations using the Charges API w...
Rails ActiveModel with type casting
## Basic usage Use `include ActiveModel::Model` and `include ActiveModel::Attributes` can provide type casting for active model. Exampl...
Precision and Scale in database
位數 (Precision) 是指數字中總共的位數。 小數位數 (Scale) 則是指數字中小數點右方的位數。 例如 123.45 的位數是 5，小數位數是 2。 precision 又稱精度 https://docs.microsoft.com/zh-tw/sql/...
How to test ActionMailer with RSpec
This blog post will demostrate how to test ActionMailer in Rails using RSpec. ## Configuration ```rb # config/environments/test.rb # T...
Rails lock! and with_lock
Basically, `ActiveRecord::Locking::Pessimistic#with_lock` will yield your code inside transaction but `ActiveRecord::Locking::Pessimistic...
How to test Stripe webhook's singature with Rspec
This post shows how to test Stripe webhook's singature ```rb # spec/support/stripe_test_helper.rb module StripeTestHelper def stripe_...
How to split rails routes.rb into smaller files - Extend
I've tried many ways to split `config/routes.rb` file, I find this approach is best to me because it requires no futher config to let dev...