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if A vs if A is not None:
...back to database stuff. There's a big difference between NULL and an empty string. An empty string typically says "there's a value here, and that value is nothing at all". NULL says "this value hasn't been entered."
In each of those cases, you'd want to use if A is None. You're checking for a speci...
PostgreSQL function for last inserted ID
...s some TRIGGER (or RULE) that, on insertion into persons table, makes some extra insertions in other tables... then LASTVAL will probably give us the wrong value. The problem can even happen with CURRVAL, if the extra insertions are done intto the same persons table (this is much less usual, but the...
Create a CSS rule / class with jQuery at runtime
...)
.appendTo("head");
Noticed the back slashes? They are used to join strings that are on new lines. Leaving them out generates an error.
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Difference between local and global indexes in DynamoDB
...OBAL_RANGE_US_TS)
@DynamoDBAttribute(attributeName = PROPERTY_USER)
public String getUser() {
return user;
}
For range index associated to the global index:
@DynamoDBIndexRangeKey(globalSecondaryIndexName = INDEX_GLOBAL_RANGE_US_TS)
@DynamoDBAttribute(attributeName = PROPERTY_TIMESTAMP)
public...
What should a Multipart HTTP request with multiple files look like? [duplicate]
... just to avoid any confusion: notice that before each boundary string in the content there are two extra dashes --<boundary>. For the last line is --<boundary>--
– Radu Simionescu
Jun 14 '13 at 12:03
...
What does the restrict keyword mean in C++?
... saved, as mentioned by supercat and michael.
Consider for example:
void f(char *restrict p1, char *restrict p2, size_t size) {
for (size_t i = 0; i < size; i++) {
p1[i] = 4;
p2[i] = 9;
}
}
Because of restrict, a smart compiler (or human), could optimize that to:
mem...
How do I use the conditional operator (? :) in Ruby?
..." : "false" then expected puts to return the boolean which then became the string value.
– Fresheyeball
Aug 25 '15 at 23:16
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Parse JSON String into a Particular Object Prototype in JavaScript
I know how to parse a JSON String and turn it into a JavaScript Object.
You can use JSON.parse() in modern browsers (and IE9+).
...
Most efficient way to check for DBNull and then assign to a variable?
...o extension methods:
public static T? GetValue<T>(this DataRow row, string columnName) where T : struct
{
if (row.IsNull(columnName))
return null;
return row[columnName] as T?;
}
public static string GetText(this DataRow row, string columnName)
{
if (row.IsNull(columnNam...
Convert to binary and keep leading zeros in Python
...most compact and direct option.
If you are putting the result in a larger string, use an formatted string literal (3.6+) or use str.format() and put the second argument for the format() function after the colon of the placeholder {:..}:
>>> value = 14
>>> f'The produced output, i...