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How do I add a placeholder on a CharField in Django?
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Look at the widgets documentation. Basically it would look like:
q = forms.CharField(label='search',
widget=forms.TextInput(attrs={'placeholder': 'Search'}))
More writing, yes, but the separation allows for better abstraction of more complic...
How do I find which program is using port 80 in Windows? [duplicate]
... Then you either need to watch through list carefully or install some additional software. technet.microsoft.com/en-us/sysinternals/bb897437.aspx for example.
– n0rd
Dec 25 '09 at 8:14
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What characters are valid for JavaScript variable names?
...ou an idea of how wrong Anthony Mills' answer is: if you were to summarize all these rules in a single ASCII-only regular expression for JavaScript, it would be 11,236 characters long. Here it is:
// ES5.1 / Unicode 6.1
/^(?!(?:do|if|in|for|let|new|try|var|case|else|enum|eval|false|null|this|true|v...
Undefined symbols for architecture i386: _OBJC_CLASS_$_SKPSMTPMessage", referenced from: error
...r the "Compile Sources" step of the "Build Phases" tab of your target. Normally Xcode does this for you, but sometimes it loses the plot and you need to add the .m file manually.
To do this:
TargetSettings -> Build Phases -> Compile Sources -> add your .m class ->Build and Run
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In Python, how can you load YAML mappings as OrderedDicts?
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Update: In python 3.6+ you probably don't need OrderedDict at all due to the new dict implementation that has been in use in pypy for some time (although considered CPython implementation detail for now).
Update: In python 3.7+, the insertion-order preservation nature of dict objects h...
About catching ANY exception
How can I write a try / except block that catches all exceptions?
8 Answers
8
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Super-simple example of C# observer/observable with delegates
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The observer pattern is usually implemented with events.
Here's an example:
using System;
class Observable
{
public event EventHandler SomethingHappened;
public void DoSomething() =>
SomethingHappened?.Invoke(this, EventArgs.Empt...
Double vs. BigDecimal?
...tudes (say d1=1000.0 and d2=0.001) could result in the 0.001 being dropped alltogether when summing as the difference in magnitude is so large. With BigDecimal this would not happen.
The disadvantage of BigDecimal is that it's slower, and it's a bit more difficult to program algorithms that way (du...
How do I capture the output of a script if it is being ran by the task scheduler?
...is as the command string in Task Scheduler:
cmd /c yourscript.cmd > logall.txt
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Geometric Mean: is there a built-in?
...pplication I had in mind they are the same, but of course this is not generally true. Thus, if you want to include optional propagation of zeros, and treat the length(x) differently in the case of NA removal, the following is a slightly longer alternative to the function above.
gm_mean = function(x...