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When to use symbols instead of strings in Ruby?
...iers. For Ruby < 2.2 only use symbols when they aren't generated dynamically, to avoid memory leaks.
Full answer
The only reason not to use them for identifiers that are generated dynamically is because of memory concerns.
This question is very common because many programming languages don't h...
Android: failed to convert @drawable/picture into a drawable
In my drawable folder I have a few images and they all reference perfect, but when I try and add any more images with the exact same size in the same folder, and try to reference it, is flags up an error "Failed to convert @drawable/picture into a drawable" . I have tried the same image with a diff...
Convenient C++ struct initialisation
...
Since style A is not allowed in C++ and you don't want style B then how about using style BX:
FooBar fb = { /*.foo=*/ 12, /*.bar=*/ 3.4 }; // :)
At least help at some extent.
...
Splitting string into multiple rows in Oracle
...ct 108 Name, 'test' Project, 'Err1, Err2, Err3' Error from dual
union all
select 109, 'test2', 'Err1' from dual
)
select distinct
t.name, t.project,
trim(regexp_substr(t.error, '[^,]+', 1, levels.column_value)) as error
from
temp t,
table(cast(multiset(select level from dual conne...
滑动菜单使用指导 · App Inventor 2 中文网
...手：底部分享面板
拖一个按钮（改名 按钮_分享）和一个标签（改名 标签_结果）；
拖一个垂直布局（改名 垂直布局_面板，宽度设为充满，取消勾选「可见」），里面放三个按钮：
按钮_微信、按钮_朋友圈、按钮...
SQLite in Android How to update a specific row
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It's actually a walk-around. The Third param of db.update() should be the where clause only, and the fourth is the actual condition values. In this case, the line should be: myDB.update(TableName, cv, "_id=?", new String[]{id}). SQLit...
Pure JavaScript Send POST Data Without a Form
... socket, SocketServer, BaseHTTPServer
import os, traceback, sys, json
log_lock = threading.Lock()
log_next_thread_id = 0
# Local log functiondef
def Log(module, msg):
with log_lock:
thread = threading.current_thread().__name__
msg = "%s %s: %s" % (module, thread...
To ARC or not to ARC? What are the pros and cons? [closed]
...t has no GC runtime overhead. The compiler inserts retains and releases in all the places you should have anyway. But it's smarter than you and can optimize out the ones that aren't actually needed (just like it can unroll loops, eliminate temporary variables, inline functions, etc.)
OK, now I will...
Can't find Request.GetOwinContext
...uget package (The nuget package name is Microsoft.AspNet.WebApi.Owin)
Install-Package Microsoft.AspNet.WebApi.Owin
See msdn here: http://msdn.microsoft.com/en-us/library/system.net.http.owinhttprequestmessageextensions.getowincontext(v=vs.118).aspx
Nuget package here: https://www.nuget.org/packa...
How to perform OR condition in django queryset?
...
from django.db.models import Q
User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True))
via Documentation
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