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原创 [ Applied Data Science with Python]week1-part2

[ Applied Data Science with Python]week1-part2string 格式化输出读写CSV文件时间string 格式化输出sales_record = {'price': 3.24,'num_items': 4,'person': 'Chris'}sales_statement = '{} bought {} item(s) at a price ...

2019-04-24 20:31:29 332

原创 [ Applied Data Science with Python]week1

[ Applied Data Science with Python]week1FunctionsTypes and SequencesTypes字符串Sequences字典SplitFunctions在Python中，你可以设置参数的预设值。例子中，我们可以重写add_numbers函数来接受三个参数，但我们可以设最后的参数为预设的None 这意味着你可以使用两个值或三个值来调用add_...

2019-04-23 21:31:27 358

原创【SQL笔记】查询连续日期

create table t (qdate datetime,vcode varchar(50));insert into t values('2013-06-01','A001');insert into t values('2013-06-02','A001');insert into t values('2013-06-02','B001');insert into t values...

2018-04-03 10:51:19 5950

原创【Python】获得多重目录下的文件

import osdef read_fileLists(path,all_files): #获得当前路径下所有文件 dirList = os.listdir(path) for f in dirList: #获得目录下文件的绝对路径 f = os.path.join(path,f) #判断该文件是否是目录类型 ...

2018-03-28 10:04:01 577

原创【Python】k-means算法实现

# -*- coding: utf-8 -*-import mathimport randomimport matplotlib.pyplot as pltfrom matplotlib import colors as m_colors#生成样本点def gen_random_sample(n_feat,lower,upper): sample=[random.unifo...

2018-03-17 15:14:22 398

原创【数据分析学习笔记】

项目分析数据：https://www.kaggle.com/osmi/mental-health-in-tech-survey，这是有关科技工作者心理健康数据的分析项目，数据是CSV格式的。数据格式部分如下：需求：统计各个国家存在的心理健康问题的男女人数代码：import numpy as npimport pandas as pd#open csv read data as datafr...

2018-03-14 18:50:06 524

原创【LeetCode】(C#)155. Min Stack(Easy)

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.push(x) -- Push element x onto stack.pop() -- Removes the element on top of the stack.top() -- Get

2017-12-27 11:21:36 221

原创【LeetCode】(C#)1. Two Sum(Easy)

Given an array of integers, return indices of the two numbers such that they add up to a specific target.You may assume that each input would have exactly one solution, and you may not use the sam

2017-12-27 11:17:52 220

原创【LeetCode】(C#)13. Roman to Integer(Easy)

Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999. public int RomanToInt(string s) { Dictionary roman=new Dictionary{{'I', 1},

2017-12-27 11:15:06 341

原创【LeetCode】(C#)461. Hamming Distance(Easy)

The Hamming distance between two integers is the number of positions at which the corresponding bits are different.Given two integers x and y, calculate the Hamming distance.Note:0 ≤ x,

2017-12-27 11:08:02 282

原创【LeetCode】(C#)389. Find the Difference(Easy)

Given two strings s and t which consist of only lowercase letters.String t is generated by random shuffling string s and then add one more letter at a random position.Find the letter that was

2017-12-27 10:55:35 221

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