大约有 47,000 项符合查询结果（耗时：0.0435秒） [XML]
Referring to the null object in Python
...Empty()
>>> empty==None
True
But then it also works on the empty string
>>> empty==''
True
And yet
>>> ''==None
False
>>> empty is None
False
Case 2: Using None as a boolean
The following two tests
if value:
# Do something
if not value:
# Do something
...
Redirect parent window from an iframe action
...ttribute is abscent all actions are allowed. If it is present and an empty string, all actions are denied.
– Marcus Harrison
Jul 3 '17 at 16:03
|
...
Rails check if yield :area is defined in content_for
...if symbol.kind_of? Symbol
symbol.to_s
elsif symbol.kind_of? String
symbol
else
raise "Parameter symbol must be string or symbol"
end
!instance_variable_get(content_var_name).nil?
end
...
How to pass the values from one activity to previous activity
....
Intent resultIntent = new Intent();
resultIntent.putExtra(PUBLIC_STATIC_STRING_IDENTIFIER, enteredTextValue);
setResult(Activity.RESULT_OK, resultIntent);
finish();
The final step is in the calling Activity: Override onActivityResult to listen for callbacks from the text entry Activity. Get the...
How to split a long regular expression into multiple lines in JavaScript?
...
You could convert it to a string and create the expression by calling new RegExp():
var myRE = new RegExp (['^(([^<>()[\]\\.,;:\\s@\"]+(\\.[^<>(),[\]\\.,;:\\s@\"]+)*)',
'|(\\".+\\"))@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\....
How do you run a SQL Server query from PowerShell?
...here is the function that I use:
function Invoke-SQL {
param(
[string] $dataSource = ".\SQLEXPRESS",
[string] $database = "MasterData",
[string] $sqlCommand = $(throw "Please specify a query.")
)
$connectionString = "Data Source=$dataSource; " +
"In...
How can you find and replace text in a file using the Windows command-line environment?
...
Replace - Replace a substring using string substitution
Description: To replace a substring with another string use the string substitution feature. The example shown here replaces all occurrences "teh" misspellings with "the" in the string variabl...
Difference between ActionBarSherlock and ActionBar Compatibility
...rderInCategory="100"
android:showAsAction="always"
android:title="@string/action1"/>
<item
android:id="@+id/action_2"
android:orderInCategory="100"
android:showAsAction="ifRoom"
android:title="@string/action2"/>
<item
android:id="@+id/action_3"
android:o...
Do sealed classes really offer performance Benefits?
...MSIL code was emitted.
public class NormalClass {
public void WriteIt(string x) {
Console.WriteLine("NormalClass");
Console.WriteLine(x);
}
}
public sealed class SealedClass {
public void WriteIt(string x) {
Console.WriteLine("SealedClass");
Console.Writ...
Compression/Decompression string with C#
I am newbie in .net. I am doing compression and decompression string in C#. There is a XML and I am converting in string and after that I am doing compression and decompression.There is no compilation error in my code except when I decompression my code and return my string, its returning only half ...