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In Python how should I test if a variable is None, True or False
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a = 'foo' if a: print 'its true' a is not actually TRUE, it's just not none
– wesm
Apr 3 '15 at 21:06
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What is the exact meaning of IFS=$'\n'?
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Normally bash doesn't interpret escape sequences in string literals. So if you write \n or "\n" or '\n', that's not a linebreak - it's the letter n (in the first case) or a backslash followed by the letter n (in the other two cas...
Draw line in UIView
...re are no errors - I wrote it without Xcode):
UIView *lineView = [[UIView alloc] initWithFrame:CGRectMake(0, 200, self.view.bounds.size.width, 1)];
lineView.backgroundColor = [UIColor blackColor];
[self.view addSubview:lineView];
[lineView release];
// You might also keep a reference to this view
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Write to .txt file?
...little piece of text into a .txt file?
I've been Googling for over 3-4 hours, but can't find out how to do it.
3 Answers
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List of lists changes reflected across sublists unexpectedly
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When you write [x]*3 you get, essentially, the list [x, x, x]. That is, a list with 3 references to the same x. When you then modify this single x it is visible via all three references to it:
x = [1] * 4
l = [x] * 3
print(f"id(x): {id(x)}")
# id(x): 1405608979...
How to darken a background using CSS?
....png);
}
Reference: linear-gradient() - CSS | MDN
UPDATE: Not all browsers support RGBa, so you should have a 'fallback color'. This color will be most likely be solid (fully opaque) ex:background:rgb(96, 96, 96). Refer to this blog for RGBa browser support.
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Find all files with a filename beginning with a specified string?
...ry with roughly 100000 files in it, and I want to perform some function on all files beginning with a specified string, which may match tens of thousands of files.
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How to check for a valid Base64 encoded string
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calling base64String.Contains multiple times may result in poor performance incase of base64String being a large string.
– NucS
Jul 23 '15 at 11:46
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What does “@” mean in Windows batch scripts
...off will turn this off for the complete batch file. However, the echo off call itself would still be visible. Which is why you see @echo off in the beginning of batch files. Turn off command echoing and don't echo the command turning it off.
Removing that line (or commenting it out) is often a help...
What it the significance of the Javascript constructor property?
...the constructor property is used in a few places. However, I think the overall gist still applies. Thanks to T. J. Crowder for pointing that out in the comments, and please read his answer for a fuller picture of the current situation.
Original answer
The constructor property makes absolutely no pra...