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How to add an empty column to a dataframe?
...t; df = pd.DataFrame({"A": [1,2,3], "B": [2,3,4]})
>>> df
A B
0 1 2
1 2 3
2 3 4
>>> df["C"] = ""
>>> df["D"] = np.nan
>>> df
A B C D
0 1 2 NaN
1 2 3 NaN
2 3 4 NaN
...
Convert int to char in java
...ascii value 49 (one corresponding to '1')
If you want to convert a digit (0-9), you can add 48 to it and cast, or something like Character.forDigit(a, 10);.
If you want to convert an int as in ascii value, you can use Character.toChars(48) for example.
...
What do the return values of node.js process.memoryUsage() stand for?
...the Heap
heapUsed: Heap actually Used
Ref: http://apmblog.dynatrace.com/2015/11/04/understanding-garbage-collection-and-hunting-memory-leaks-in-node-js/
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How to convert byte array to Bitmap
...am blob = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 0 /* Ignored for PNGs */, blob);
byte[] bitmapdata = blob.toByteArray();
If bitmapdata is the byte array then getting Bitmap is done like this:
Bitmap bitmap = BitmapFactory.decodeByteArray(bitmapdata, 0, bitmapdata.length...
What's the difference between echo, print, and print_r in PHP?
...s you have in your variables. Consider this test program:
$values = array(0, 0.0, false, '');
var_dump($values);
print_r ($values);
With print_r you can't tell the difference between 0 and 0.0, or false and '':
array(4) {
[0]=>
int(0)
[1]=>
float(0)
[2]=>
bool(false)
[3]=...
SyntaxError: Use of const in strict mode
...
10 Answers
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How to send only one UDP packet with netcat?
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205
If you are using bash, you might as well write
echo -n "hello" >/dev/udp/localhost/8000
a...
Python module os.chmod(file, 664) does not change the permission to rw-rw-r— but -w--wx----
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130
Found this on a different forum
If you're wondering why that leading zero is important, it's...
Install a .NET windows service without InstallUtil.exe
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answered Oct 31 '08 at 21:49
Marc Gravell♦Marc Gravell
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How can I delete a query string parameter in JavaScript?
...iteration as may be destructive
for (var i = pars.length; i-- > 0;) {
//idiom for string.startsWith
if (pars[i].lastIndexOf(prefix, 0) !== -1) {
pars.splice(i, 1);
}
}
return urlparts[0] + (pars.length > 0 ? '?'...