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Why are #ifndef and #define used in C++ header files?
...he header is included, it checks if a unique value (in this case HEADERFILE_H) is defined. Then if it's not defined, it defines it and continues to the rest of the page.
When the code is included again, the first ifndef fails, resulting in a blank file.
That prevents double declaration of any iden...
How to read a large file - line by line?
... The for line in f treats the file object f as an iterable, which automatically uses buffered I/O and memory management so you don't have to worry about large files.
There should be one -- and preferably only one -- obvious way to do it.
...
Ideal Ruby project structure
...pname folder because most libraries are in the appname namespace.
Additionally, if you try running the command newgem --simple [projectname] that'll quickly generate a scaffold for you with just the bare essentials for a Ruby project (and by extension a Ruby Gem). There are other tools which do thi...
Convenient C++ struct initialisation
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Since style A is not allowed in C++ and you don't want style B then how about using style BX:
FooBar fb = { /*.foo=*/ 12, /*.bar=*/ 3.4 }; // :)
At least help at some extent.
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What is SQL injection? [duplicate]
...sult of queries, reading data or even changing data that they shouldn't be allowed to do.
Example in PHP:
$password = $_POST['password'];
$id = $_POST['id'];
$sql = "UPDATE Accounts SET PASSWORD = '$password' WHERE account_id = $id";
Now suppose the attacker sets the POST request parameters to "...
java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F…'
...ead:
For a supplementary character, utf8 cannot store the character at all,
while utf8mb4 requires four bytes to store it. Since utf8 cannot store
the character at all, you do not have any supplementary characters in
utf8 columns and you need not worry about converting characters or
losi...
What is the closest thing Windows has to fork()?
I guess the question says it all.
13 Answers
13
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how do you filter pandas dataframes by multiple columns
...r function using query in pandas. Here you have filtering of df results by all the kwargs parameters. Dont' forgot to add some validators(kwargs filtering) to get filter function for your own df.
def filter(df, **kwargs):
query_list = []
for key in kwargs.keys():
query_list.append(f...
How do you convert a byte array to a hexadecimal string, and vice versa?
...
You're using SubString. Doesn't this loop allocate a horrible amount of string objects?
– Wim Coenen
Mar 6 '09 at 16:36
30
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Detecting request type in PHP (GET, POST, PUT or DELETE)
...
By using
$_SERVER['REQUEST_METHOD']
Example
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
// The request is using the POST method
}
For more details please see the documentation for the $_SERVER variable.
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