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Tricks to manage the available memory in an R session
...lumns by reference
Modify subsets of existing columns by reference, and by group by reference
Delete columns by reference
None of these operations copy the (potentially large) data.table at all, not even once.
Aggregation is also particularly fast because data.table uses much less working memory...
Get first day of week in SQL Server
I am trying to group records by week, storing the aggregated date as the first day of the week. However, the standard technique I use for rounding off dates does not appear to work correctly with weeks (though it does for days, months, years, quarters and any other timeframe I've applied it to).
...
Difference between scaling horizontally and vertically for databases [closed]
...i As explained here, vertical scaling is limited to one server (or a small group of servers) and it has a practical upper limit (meaning you can't go beyond say 512 GB of RAM). Horizontal scaling on the other hand can practically happen indefinitely.
– asgs
Jun...
Creating a new user and password with Ansible
...{ uusername }}
password: {{ upassword | password_hash('sha512') }}
groups: admin append=yes
when: assigned_role == "yes"
- name: Creating users "{{ uusername }}" without admin access
user:
name: {{ uusername }}
password: {{ upassword | password_hash('sha512') }}
when: assig...
Hidden features of Python [closed]
...10). You can even apply them to single arguments, like (= 10): cs.cmu.edu/Groups/AI/html/hyperspec/HyperSpec/Body/…
– Ken
May 26 '10 at 20:31
|
...
What's the difference between a word and byte?
...aziness) - it is easier to say "byte" rather than "eight bits"
tribalism - groups of people like to use jargon / a private language to set them apart from others.
Just go with the flow. You are not going to change 50+ years of accumulated IT terminology and cultural baggage by complaining about i...
Visual SVN 安装及客户端使用 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...的用户,点击OK按钮：
说明：大家可能注意到了下图中的Groups，是的，你也可以先创建组，把用户添加到各个组中，然后对组进行授权，操作比较简单，在此略过。
按照下图所示，分别对用户【或组】进行授权：
点击"确定"...
How to create a printable Twitter-Bootstrap page
...99;
page-break-inside: avoid;
}
thead {
display: table-header-group;
}
tr,
img {
page-break-inside: avoid;
}
img {
max-width: 100% !important;
}
p,
h2,
h3 {
orphans: 3;
widows: 3;
}
h2,
h3 {
page-break-after: avoid;
}
select {
backgrou...
What is the difference between gsub and sub methods for Ruby Strings
...nly seems to be finding/replacing only the first instance when using regex groups?
– Bennett Talpers
Jul 25 '18 at 18:26
...
SecItemAdd and SecItemCopyMatching returns error code -34018 (errSecMissingEntitlement)
... project
settings->Capabilities->Keychain Sharing->Add Keychain Groups+Turn On
An answer here, from Apple:
UPDATE: We have finally been able to reproduce the -34018 error on iOS
8.3. This is the first step in identifying the root cause and then coming up with a fix.
As usual...