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How do I read any request header in PHP
...header fields, if the protocol used is HTTP. The HTTP header field name is converted to upper case, has all occurrences of - replaced with _ and has HTTP_ prepended to give the meta-variable name.
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String is immutable. What exactly is the meaning? [duplicate]
...e proceeding further with the fuss of immutability, let's just take a look into the String class and its functionality a little before coming to any conclusion.
This is how String works:
String str = "knowledge";
This, as usual, creates a string containing "knowledge" and assigns it a reference ...
Returning value that was passed into a method
I have a method on an interface:
3 Answers
3
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PSQLException: current transaction is aborted, commands ignored until end of transaction block
...e statement to illustrate the Exception:
CREATE TABLE moobar
(
myval INT
);
Java program causes the error:
public void postgresql_insert()
{
try
{
connection.setAutoCommit(false); //start of transaction.
Statement statement = connection.createStatement();
...
Slicing of a NumPy 2d array, or how do I extract an mxm submatrix from an nxn array (n>m)?
... x from your question. The buffer assigned to x will contain 16 ascending integers from 0 to 15. If you access one element, say x[i,j], NumPy has to figure out the memory location of this element relative to the beginning of the buffer. This is done by calculating in effect i*x.shape[1]+j (and mu...
Is there a regular expression to detect a valid regular expression?
...n directly. (The (?1) and (?R) constructs.) The recursion would have to be converted to counting balanced groups:
^ # start of string
(?:
(?: [^?+*{}()[\]\\|]+ # literals and ^, $
| \\. # escaped charact...
Label encoding across multiple columns in scikit-learn
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We don't need a LabelEncoder.
You can convert the columns to categoricals and then get their codes. I used a dictionary comprehension below to apply this process to every column and wrap the result back into a dataframe of the same shape with identical indices a...
Check if a string matches a regex in Bash script
...is in the correct format, it is best to parse it with date and ask date to convert the string to the correct format. If both strings are identical, you have a valid format and valid date.
if [[ "$datestr" == $(date -d "$datestr" "+%Y%m%d" 2>/dev/null) ]]; then
echo "Valid date"
else
e...
How to check whether an array is empty using PHP?
...er(): If no callback is supplied, all entries of array equal to FALSE (see converting to boolean) will be removed.
If you'd like to remove all NULL, FALSE and empty strings (''), but leave zero values (0), you can use strlen as a callback, e.g.:
$is_empty = array_filter($playerlist, 'strlen') == ...
Null or default comparison of generic argument in C#
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For me this doesn't work when using integers that are already boxed. Because it will then be an object and the default for object is null instead of 0.
– riezebosch
Nov 7 '11 at 19:11
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