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psql invalid command \N while restore sql
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Postgres uses "\N" as substitute symbol for NULL value. But all psql commands starts by backslash "\" symbol. So you can get this messages, when probably copy statement fails, but a loading of dump continues. This message is only false alarm. You have to search a lines before for reas...
Round to at most 2 decimal places (only if necessary)
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@James Wow that's really weird- I'm working in the Chrome dev console and I'm noticing that 1.005 * 100 = 100.49999999999999. Math.round(100.49999999999999) evaluates to 100, whereas Math.round(100.5) evaluates to 101. IE9 does the same thing. T...
if/else in a list comprehension
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You can totally do that. It's just an ordering issue:
[unicode(x.strip()) if x is not None else '' for x in row]
In general,
[f(x) if condition else g(x) for x in sequence]
And, for list comprehensions with if conditions only,
[f...
Difference between sh and bash
When writing shell programs, we often use /bin/sh and /bin/bash . I usually use bash , but I don't know what's the difference between them.
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How to Convert all strings in List to lower case using LINQ?
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Easiest approach:
myList = myList.ConvertAll(d => d.ToLower());
Not too much different than your example code. ForEach loops the original list whereas ConvertAll creates a new one which you need to reassign.
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Batch file. Delete all files and folders in a directory
I want to have a batch file that will delete all the folders and files in my cache folder for my wireless toolkit.
15 Answe...
Show an image preview before upload
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HTML5 comes with File API spec, which allows you to create applications that let the user interact with files locally; That means you can load files and render them in the browser without actually having to upload the files. Part of the File API is the FileReader...
Wrapping StopWatch timing with a delegate or lambda?
... sw.Stop();
return sw.ElapsedMilliseconds;
}
}
Then call it like this:
var s = new Stopwatch();
Console.WriteLine(s.Time(() => DoStuff(), 1000));
You could add another overload which omits the "iterations" parameter and calls this version with some default value (like 100...
What is a predicate in c#? [duplicate]
...cate<T> is a functional construct providing a convenient way of basically testing if something is true of a given T object.
For example suppose I have a class:
class Person {
public string Name { get; set; }
public int Age { get; set; }
}
Now let's say I have a List<Person> p...
Why are Python lambdas useful? [closed]
...ut lambda functions? Like
lambda x: x**2 + 2*x - 5
Those things are actually quite useful. Python supports a style of programming called functional programming where you can pass functions to other functions to do stuff. Example:
mult3 = filter(lambda x: x % 3 == 0, [1, 2, 3, 4, 5, 6, 7, 8, 9])...