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How do I clear only a few specific objects from the workspace?
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what if I want to remove all variables with names start with letter A, say 'A001', 'A002'.... 'A999'. I don't want to type so many variable names. Thanks!
– user3768495
Sep 22 '15 at 16:04
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rails 3 validation on uniqueness on multiple attributes
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I would add that if you want to use :scope on foreign keys, you need to use the :fkey_id symbols, instead of :fkey ones, even if a "basic" :uniqueness works on :fkey
– nbarraille
Sep 7 '12 at 2:48
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How to reuse an ostringstream?
...lt;< "hello";
s.seekp(0);
s << "b";
assert(s.str() == "bello");
If you want to use the string for c-functions, you can use std::ends, putting a terminating null like this:
std::ostringstream s;
s << "hello";
s.seekp(0);
s << "b" << std::ends;
assert(s.str().size() == 5 ...
C++ const map element access
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Rather than insert a new default constructed element as operator[] does if an element with the given key does not exist, it throws a std::out_of_range exception. (This is similar to the behaviour of at() for deque and vector.)
Because of this behaviour it makes sense for there to be a const over...
Add primary key to existing table
...ption in the case of composite PKs for performance on insertion date basis if that is important for you.
– Shiv
Feb 10 '17 at 5:23
add a comment
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Which access modifiers are implied when not specified?
For all of the different concepts that support access modifiers, such as fields, properties, methods and classes, which access modifiers are implied if not specified?
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IE8 and JQuery's trim()
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Try this instead:
if($.trim($('#group_field').val()) != ''){
More Info:
http://api.jquery.com/jQuery.trim/
share
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improve this answer
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Is there a way to check if int is legal enum in C#?
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Check out Enum.IsDefined
Usage:
if(Enum.IsDefined(typeof(MyEnum), value))
MyEnum a = (MyEnum)value;
This is the example from that page:
using System;
[Flags] public enum PetType
{
None = 0, Dog = 1, Cat = 2, Rodent = 4, Bird = 8, Reptile = 16...
Stop pip from failing on single package when installing with requirements.txt
...out the -a flag, consider < requirements.txt xargs -n 1 pip install, or if you don't like the redirect at the front, xargs -n 1 pip install < requirements.txt. :-)
– torek
Jul 6 at 17:21
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How to redirect the output of an application in background to /dev/null
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You use:
yourcommand > /dev/null 2>&1
If it should run in the Background add an &
yourcommand > /dev/null 2>&1 &
>/dev/null 2>&1 means redirect stdout to /dev/null AND stderr to the place where stdout points at that time
If you wan...