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Algorithm

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
Example 1:

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Input: 121
Output: true

Example 2:

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Input: -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 3:

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Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

answer

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class Solution(object):
    def isPalindrome(self, x):
        """
        :type x: int
        :rtype: bool
        """
        return str(x) == str(x)[::-1]

Rewiew

https://towardsdatascience.com/10-git-commands-you-should-know-df54bea1595c
文章介绍了平时开发过程中常用的git命令，以及如何利用别名更快的使用git命令。

Tip

近期在做项目时有一个类似规则引擎的需求，就是根据消息中某些字段的值判断需要执行的处理函数，期望能通过配置实现。调研了部分规则引擎，最终选择business_rules的开源工具，git地址为https://github.com/venmo/business-rules 。使用方式简单，编写变量类，动作类，通过规则配置变量条件与动作的映射关系。实例代码如下:

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#!/usr/bin/env python
# -*- coding: utf-8 -*-
import datetime

from business_rules.variables import BaseVariables
from business_rules.variables import numeric_rule_variable, string_rule_variable, select_rule_variable
from business_rules.actions import BaseActions, rule_action
from business_rules.fields import FIELD_NUMERIC, FIELD_SELECT
from business_rules import run_all


class ProductVariables(BaseVariables):

    def __init__(self, product):
        self.product = product

    @numeric_rule_variable
    def current_inventory(self):
        return self.product.current_inventory

    @numeric_rule_variable(label='Days until expiration')
    def expiration_days(self):
        last_order = self.product.orders[-1]
        return (last_order.expiration_date - datetime.date.today()).days

    @string_rule_variable()
    def current_month(self):
        return datetime.datetime.now().strftime("%B")



class ProductActions(BaseActions):

    def __init__(self, product):
        self.product = product

    @rule_action(params={"sale_percentage": FIELD_NUMERIC})
    def put_on_sale(self, sale_percentage):
        self.product.price = (1.0 - sale_percentage) * self.product.price
        self.product.save()

    @rule_action(params=[{'fieldType': FIELD_SELECT,
                          'name': 'stock_state',
                          'label': 'Stock state',
                          'options': [
                            {'label': 'Available', 'name': 'available'},
                            {'label': 'Last items', 'name': 'last_items'},
                            {'label': 'Out of stock', 'name': 'out_of_stock'}
                        ]}])
    def change_stock_state(self, stock_state):
        self.product.stock_state = stock_state
        self.product.save()


rules = [
# expiration_days < 5 AND current_inventory > 20
{ "conditions": { "all": [
      { "name": "current_inventory",
        "operator": "greater_than",
        "value": 20,
      },
  ]},
  "actions": [
      { "name": "put_on_sale",
        "params": {"sale_percentage": 0.25},
      },
  ],
},
]
class Product(object):

    def __init__(self):
        self.current_inventory = 100
        self.price = 1

    def save(self):
        print("save....{},{}".format(self.current_inventory, self.price))
        
product = Product()

run_all(rule_list=rules,
        defined_variables=ProductVariables(product),
        defined_actions=ProductActions(product),
        stop_on_first_trigger=True
       )

ProductVariables为变量类，定义了某变量与变量类成员变量的关系；ProductActions为动作类，定义了处理函数；
rules定义了某条件下调用的处理函数；通过调用run_all()即可运行该规则引擎。

Share

https://www.cloudamqp.com/blog/2015-05-18-part1-rabbitmq-for-beginners-what-is-rabbitmq.html
对rabbit mq进行介绍的系列文章，可以对rabbit mq有初步认识，理解相关概念。