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What's the difference between [ and [[ in Bash? [duplicate]
...e. You no longer have to quote variables like mad because [[ handles empty strings and strings with whitespace more intuitively. For example, with [ you have to write
if [ -f "$file" ]
to correctly handle empty strings or file names with spaces in them. With [[ the quotes are unnecessary:
if [[ ...
Can I simultaneously declare and assign a variable in VBA?
...character if you want it on one line for readability;
Dim clientToTest As String: clientToTest = clientsToTest(i)
Dim clientString As Variant: clientString = Split(clientToTest)
Hint (summary of other answers/comments): Works with objects too (Excel 2010):
Dim ws As Worksheet: Set ws = Activ...
How do I modify fields inside the new PostgreSQL JSON datatype?
..._build_object('<key>', '<value>')
Where <key> should be string, and <value> can be whatever type to_jsonb() accepts.
For setting a value deep in a JSON hierarchy, the jsonb_set() function can be used:
SELECT jsonb_set('{"a":[null,{"b":[]}]}', '{a,1,b,0}', jsonb '{"c":3}')
--...
How can I convert spaces to tabs in Vim or Linux?
...k for all your text, not only spaces in the begin of the line. That mean a string like: "Hey,␣this␣␣␣␣is␣4␣spaces" will become "Hey,␣this⇥is␣4␣spaces", but its not! its a tab!.
To settle this little problem I recomend a search, instead of retab.
:%s/^\(^I*\)␣␣␣␣/\1^I/g
...
What is null in Java?
...s another usage example, this time from java.io.BufferedReader:
public String readLine() throws IOException
Returns: A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached.
So here, readLine() would re...
How can I get enum possible values in a MySQL database?
...
You can get the values by querying it like this:
SELECT SUBSTRING(COLUMN_TYPE,5)
FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA='databasename'
AND TABLE_NAME='tablename'
AND COLUMN_NAME='columnname'
From there you'll need to convert it into an array:
eval that direct...
How to use a variable for the key part of a map
... value-part it's even easier, since there is no automagic "convert text to string" happening:
def map = [keyA:A, keyX:X]
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How to tell Jackson to ignore a field during serialization if its value is null?
...ion(Include.NON_NULL);
or:
@JsonInclude(Include.NON_NULL)
class Foo
{
String bar;
}
Alternatively, you could use @JsonInclude in a getter so that the attribute would be shown if the value is not null.
A more complete example is available in my answer to How to prevent null values inside a Ma...
Android - Using Custom Font
...blic class CustomFontTextView extends TextView {
private static final String sScheme =
"http://schemas.android.com/apk/res-auto";
private static final String sAttribute = "customFont";
static enum CustomFont {
ROBOTO_THIN("fonts/Roboto-Thin.ttf"),
ROBOTO_LIG...
Group by in LINQ
...Collections.Generic;
class Person
{
public int PersonId;
public string car ;
}
class Result
{
public int PersonId;
public List<string> Cars;
}
public class Program
{
public static void Main()
{
List<Person> persons = new List<Person>()
...