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Pandas every nth row
...simpler solution to the accepted answer that involves directly invoking df.__getitem__.
df = pd.DataFrame('x', index=range(5), columns=list('abc'))
df
a b c
0 x x x
1 x x x
2 x x x
3 x x x
4 x x x
For example, to get every 2 rows, you can do
df[::2]
a b c
0 x x x
...
Linux下部署企业级邮件服务器(postfix + dovecot + extmail) - 开源 & Gith...
...环境配置
1、安装一下过程中所依赖的一些rpm包
yum install -y tcl-devel libart_lgpl-devel libtool-ltdl-devel
2、关闭sendmail，并取消其开机启动
service sendmail stop
chkconfig sendmail off
3、配置编译环境，安装开发包组
yum groupinstall -y "Develop...
What is RSS and VSZ in Linux memory management
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RSS is the Resident Set Size and is used to show how much memory is allocated to that process and is in RAM. It does not include memory that is swapped out. It does include memory from shared libraries as long as the pages from those libraries are actually in memory. It does include all st...
How to create SBT project with IntelliJ Idea?
...Sbt developing, and I'd like to import a Sbt project in IntelliJ Idea.
Actually, I managed to import my project in two different ways:
...
mysql :: insert into table, data from another table?
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INSERT INTO action_2_members (campaign_id, mobile, vote, vote_date)
SELECT campaign_id, from_number, received_msg, date_received
FROM `received_txts`
WHERE `campaign_id` = '8'
...
Remove all occurrences of char from string
...argument is regular expression, sometimes it won't work as expected, especially if this string comes from user input.
– vbezhenar
Jul 4 '12 at 8:50
9
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Entity Framework: There is already an open DataReader associated with this Command
I am using Entity Framework and occasionally i will get this error.
17 Answers
17
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How to define a preprocessor symbol in Xcode
..., and select "Add User-Defined Setting". The new setting name should be GCC_PREPROCESSOR_DEFINITIONS, and you can type your definitions in the right-hand field.
Per Steph's comments, the full syntax is:
constant_1=VALUE constant_2=VALUE
Note that you don't need the '='s if you just want to #defi...
What is the difference between is_a and instanceof?
...ut PHP versions >= 5.3.9 now accept an optional third boolean argument $allow_string (defaults to false) to allow comparisons of string class names instead:
class MyBaseClass {}
class MyExtendingClass extends MyBaseClass {}
// Original behavior, evaluates to false.
is_a(MyExtendingClass::class,...
ZMQ: 基本原理 - 开源 & Github - 清泛网 - 专注C++内核技术
... 为了强化这个原则，ØMQ严格地分离拓扑的建立（zmq_bind,zmq_connect）和真实消息的传递（zmq_send,zmq_rev)。 前者同底层的传输地址协同工作，比如IP地址，而后者仅仅使用处理器（文件描述符）去定位具体的拓扑： /* Topology esta...