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笨法玩电商网站秒杀 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...参考我以前写的「Redis消息通知系统的实现」。
把请求保存到队列里之后，可以通过Gearman实现Worker来消费队列，请求的生产和消费是异步的，所以不会出现并发拥堵，但是可能发生延迟，如果出现这种情况，可以通过增加Worker...
从Sloodle看三维虚拟学习环境的发展趋势 - 资讯 - 清泛网 - 专注C/C++及内核技术
...的使用。这些系统中的工具支持大部分教学中的特征 ,如文件共享、讨论、任务 ,以及与教学信息系统的整合。
另一方面 ,大型多人在线游戏 (Massively Multip layer Online Games,MMOG)也逐渐变为大众游戏 ,吸引了越来越多的关注。现在...
How to export DataTable to Excel
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Try simple code, to convert DataTable to excel file as csv:
var lines = new List<string>();
string[] columnNames = dataTable.Columns
.Cast<DataColumn>()
.Select(column => column.ColumnName)
.ToArray();
var header = string.Join(",", columnNames.Select...
Subset of rows containing NA (missing) values in a chosen column of a data frame
We have a data frame from a CSV file. The data frame DF has columns that contain observed values and a column ( VaR2 ) that contains the date at which a measurement has been taken. If the date was not recorded, the CSV file contains the value NA , for missing data.
...
Split a string by spaces — preserving quoted substrings — in Python
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Depending on your use case, you may also want to check out the csv module:
import csv
lines = ['this is "a string"', 'and more "stuff"']
for row in csv.reader(lines, delimiter=" "):
print(row)
Output:
['this', 'is', 'a string']
['and', 'more', 'stuff']
...
List of tables, db schema, dump etc using the Python sqlite3 API
...se.db')
table = pd.read_sql_query("SELECT * from table_name", db)
table.to_csv(table_name + '.csv', index_label='index')
Dump all tables:
import sqlite3
import pandas as pd
def to_csv():
db = sqlite3.connect('database.db')
cursor = db.cursor()
cursor.execute("SELECT name FROM sqlite...
How do I convert dates in a Pandas data frame to a 'date' data type?
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I imagine a lot of data comes into Pandas from CSV files, in which case you can simply convert the date during the initial CSV read:
dfcsv = pd.read_csv('xyz.csv', parse_dates=[0]) where the 0 refers to the column the date is in.
You could also add , index_col=0 in there...
PostgreSQL query to return results as a comma separated list
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You can generate a CSV from any SQL query using psql:
$ psql
> \o myfile.csv
> \f ','
> \a
> SELECT col1 AS column1, col2 AS column2 ... FROM ...
The resulting myfile.csv will have the SQL resultset column names as CSV column h...
Is Response.End() considered harmful?
...rmation on response.end so for other searches like myself who wish to post CSV/XML/PDF etc in response to an event without rendering the entire ASPX page, this is how I do it. (overriding the render methods is overly complex for such a simple task IMO)
// Add headers for a csv file or whatever
Resp...
Java: splitting a comma-separated string but ignoring commas in quotes
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http://sourceforge.net/projects/javacsv/
https://github.com/pupi1985/JavaCSV-Reloaded
(fork of the previous library that will allow the generated output to have Windows line terminators \r\n when not running Windows)
http://opencsv.sourceforge.net/
CSV API f...