attributes interview questions
Top attributes frequently asked interview questions
I have an form input element and want to change its title attribute. This has to be easy as pie, but for some reason I cannot find how to do this. How is this done, and where and how should I be searching on how to do this?
Source: (StackOverflow)
Suppose I have a python object x
and a string s
, how do I set the attribute s
on x
? So:
>>> x = SomeObject()
>>> attr = 'myAttr'
>>> # magic goes here
>>> x.myAttr
'magic'
What's the magic? The goal of this, incidentally, is to cache calls to x.__getattr__()
.
Source: (StackOverflow)
Is it possible to add attributes at runtime or to change the value of an attribute at runtime?
Source: (StackOverflow)
Is there any meaningful distinction between:
class A(object):
foo = 5 # some default value
vs.
class B(object):
def __init__(self, foo=5):
self.foo = foo
If you're creating a lot of instances, is there any difference in performance or space requirements for the two styles? When you read the code, do you consider the meaning of the two styles to be significantly different?
Source: (StackOverflow)
I want to do so:
ng-hide="!globals.isAdmin && mapping.is_default"
but the expression evaluates always to false
.
I do not want to define special function on $scope
.
Source: (StackOverflow)
Is there a best-practice indication about using setAttribute instead of the dot (.) attribute notation?
e.g.
myObj.setAttribute("class","nameOfClass");
- and -
myObj.className="nameOfClass";
OR
myObj.setAttribute("id","someID");
- and -
myObj.id="someID";
etc
Thank you.
Source: (StackOverflow)
Question based on MSDN example.
Let's say we have some C# classes with HelpAttribute in standalone desktop application. Is it possible to enumerate all classes with such attribute? Does it make sense to recognize classes this way? Custom attribute would be used to list possible menu options, selecting item will bring to screen instance of such class. Number of classes/items will grow slowly, but this way we can avoid enumerating them all elsewhere, I think.
Source: (StackOverflow)
Is there a way in Python to determine if an object has some attribute? For example:
>>> a = SomeClass()
>>> a.someProperty = value
>>> a.property
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: SomeClass instance has no attribute 'property'
How can you tell if a
has the attribute property
before using it?
Source: (StackOverflow)
I have created a JS class to populate SG/Folder list view data, when items are modified. (As per Jaime's approach)
Everything works great when I operate on items in the publication they're created in.
Ex: I open a component or page and the custom locked by
column immediately updates and shows my user name.
However, when I go to a child publication and repeat that process, I get the window asking if I want to localize or edit the parent item. If I select to edit the parent window, the code doesn't work. I haven't quite figured it out yet with initial debugging. Chrome seems to swallow the error, Firefox gives me a cryptic:
Timestamp: 6/22/2012 3:42:54 PM
Error: uncaught exception: [Exception... "Component returned failure code: 0x80004002
(NS_NOINTERFACE) [nsIWebProgress.DOMWindow]" nsresult: "0x80004002 (NS_NOINTERFACE)"
location: "JS frame :: chrome://browser/content/tabbrowser.xml :: :: line 545"
data: no]
Does anyone have any initial ideas? I'll try to post some code later on...
Code from PageEx.js:
Type.registerNamespace("MyCompany.Tridion.RTFExtensions");
/*
* Constructor
*/
MyCompany.Tridion.RTFExtensions.PageEx = function (id) {
Type.enableInterface(this, "MyCompany.Tridion.RTFExtensions.PageEx");
this.addInterface("Tridion.ContentManager.Page", [id]);
var p = this.properties;
p.versionNumberString = undefined;
p.modifiedBy = undefined;
p.lockedBy = undefined;
p.approvalStatus = undefined;
p.publishDate = undefined;
p.previousVersion = undefined;
p.previousApprovalStatus = undefined;
p.customModifiedDate = undefined;
p.initialModifierUserName = undefined;
};
/*
* sends the list xml string for the item
*/
MyCompany.Tridion.RTFExtensions.PageEx.prototype.getListItemXmlAttributes = function (customAttributes) {
var attribs = {};
$extUtils.getListItemXmlAttributes(customAttributes,this, attribs);
return this.callBase("Tridion.ContentManager.Page", "getListItemXmlAttributes", [attribs]);
};
/*
* This method gets called when an item is opened from list view. node parameter has the information
* displayed in the list view as attributes. We are getting cutom data extender column information
* from this xml node and storing it in this class member for returning it from getListItemXmlAttributes method
*/
MyCompany.Tridion.RTFExtensions.PageEx.prototype.setDataFromList = function (node, parentId, timeStamp) {
$extUtils.setDataFromList(node,parentId,timeStamp,this);
this.callBase("Tridion.ContentManager.Page", "setDataFromList", [node, parentId, timeStamp]);
};
/*
* Gets item icon
*/
MyCompany.Tridion.RTFExtensions.PageEx.prototype.getItemIcon = function () {
var icon = this.callBase(this.defaultBase, "getItemIcon");
return icon;
};
Code from utils.js:
// reloads the list view for the given id (used in list view data refresh when JS cant get the required data without reloading)
MyCompany.Tridion.RTFExtensions.Utilities.reloadListView = function (listTcmId) {
var registry = $models.getListsRegistry();
for(var key in registry)
{
var entry = $models.getItem(registry[key]);
if (entry && entry.getParentId() == listTcmId)
{
entry.unload();
return true;
}
}
return false;
}
/*
* This method gets called when an item is opened from list view. node parameter has the information
* displayed in the list view as attributes. We are getting cutom data extender column information
* from this xml node and storing it in this class member for returning it from getListItemXmlAttributes method
*/
MyCompany.Tridion.RTFExtensions.Utilities.setDataFromList = function (node, parentId, timeStamp, itemClicked) {
var p = itemClicked.properties;
if (!timeStamp || timeStamp > itemClicked.getTimeStamp()) {
var tmp;
if (tmp = node.getAttribute('Version')) {
p.versionNumberString = tmp;
p.previousVersion = tmp;
}
if (tmp = node.getAttribute('ModifiedBy')) {
p.modifiedBy = tmp;
p.initialModifierUserName = tmp;
}
if (tmp = node.getAttribute('LockedBy')) {
p.lockedBy = tmp;
}
if (tmp = node.getAttribute('ApprovalStatus')) {
p.approvalStatus = tmp;
p.previousApprovalStatus = tmp;
}
if (tmp = node.getAttribute('PublishDate')) {
p.publishDate = tmp;
}
if (p.customModifiedDate === undefined) {
if (tmp = node.getAttribute('Modified')) {
p.customModifiedDate = tmp;
}
}
}
}
/*
* sends the list xml string for the item in the list view.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListItemXmlAttributes = function (customAttributes, listViewObject,attribs) {
var p = listViewObject.properties;
$extUtils.getListViewItemLockedByName(p,listViewObject);
if (customAttributes) {
for (var attr in customAttributes) {
attribs[attr] = customAttributes[attr];
}
}
attribs["Version"] = $extUtils.getListViewItemUpdatedVersion(p,listViewObject);
//modified name has to come after the version update...
$extUtils.getListViewItemModifiedByName(p,listViewObject);
attribs["ApprovalStatus"] = $extUtils.getListViewItemApprovalStatus(p,listViewObject);
attribs["PublishDate"] = $extUtils.getListViewItemPublishDate(p,listViewObject);
//set default values
if (p.versionNumberString != undefined) {
var iResult = p.versionNumberString.localeCompare(p.previousVersion);
if (p.previousVersion === undefined || iResult > 0) {
//it's been updated!
p.previousVersion = p.versionNumberString;
p.previousApprovalStatus = p.approvalStatus;
//also need to update modified date
p.customModifiedDate = $extUtils.getListViewItemUpdatedModifiedDate(p,listViewObject);
p.initialModifierUserName = p.modifiedBy;
}
}
attribs["Modified"] = p.customModifiedDate;
attribs["LockedBy"] = p.lockedBy;
attribs["ModifiedBy"] = p.modifiedBy;
};
/*
* This method sets the property of the Revisor owner on the item in the list view. however, if it's not the current user
* we have no way to look that up in JS so we have to reload the list view.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemModifiedByName = function (p,listViewObject) {
var p = listViewObject.properties;
var xmlDoc = listViewObject.getXmlDocument();
if (xmlDoc) {
//modifier should always exist...
var modifierId = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:Revisor/@xlink:title");
if (modifierId != undefined) {
var u = Tridion.UI.UserSettings.getJsonUserSettings(true);
if (modifierId == u.User.Data.Name) {
var strDescription = u.User.Data.Description.split('(');
p.modifiedBy = strDescription[0];
return;
} else {
//we're in trouble...
//let's hope it's the initial modifier we had...
if (p.previousVersion == p.versionNumberString) {
//whew...
p.modifiedBy = p.initialModifierUserName;
return;
}
if (!$extUtils.reloadListView(listViewObject.getOrganizationalItemId())) {
//hrm. something failed on the reload? not sure what else to do:
p.modifiedBy = modifierId;
}
}
} else {
//shouldn't ever happen.
p.modifiedBy = "";
return;
}
}
};
/*
* This method sets the property of the lock owner on the item in the list view. however, if it's not the current user
* we have no way to look that up in JS so we have to reload the list view.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemLockedByName = function (p,listViewObject) {
var xmlDoc = listViewObject.getXmlDocument();
if (xmlDoc) {
//this will be user id. no sense getting tcmid... can't look it up without async call
var lockedUserId = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:ItemLock/tcm:User/@xlink:title");
if (lockedUserId != undefined) {
//see if it's the current user. most likely...
var u = Tridion.UI.UserSettings.getJsonUserSettings(true);
if (lockedUserId == u.User.Data.Name) {
var strDescription = u.User.Data.Description.split('(');
p.lockedBy = strDescription[0];
return;
}
//it's not the current user. no synch way to do what we want, plus the JS call doesn't get the workflow version anyway. refresh the parent view
if (!$extUtils.reloadListView(listViewObject.getOrganizationalItemId())) {
//hrm. something failed on the reload? not sure what else to do:
p.lockedBy = lockedUserId;
}
} else {
//clear it out since there's no lock owner
p.lockedBy = "";
}
}
};
/*
* Gets the ApprovalStatus from the item
* This makes absolutely no sense... but for some reason the approval status gets wiped out when this method
* enters. so I had to use a "previous approval status" variable to maintain it. no idea why. I don't see anything
* else that should be touching it... but clearly something clears it out.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemApprovalStatus = function (p,listViewObject) {
//check if the item has actually been modified.
if (p.versionNumberString != p.previousVersion) {
var xmlDoc = listViewObject.getXmlDocument();
if (xmlDoc) {
p.approvalStatus = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:Data/tcm:ApprovalStatus/@xlink:title");
}
} else {
p.approvalStatus = p.previousApprovalStatus;
}
if (p.approvalStatus === undefined || p.approvalStatus.toUpperCase() == 'UNAPPROVED') {
var foo = p.approvalStatus;
p.approvalStatus = 'WIP';
}
return p.approvalStatus;
};
/*
* Gets the PublishDate from the item list view
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemPublishDate = function (p,listViewObject) {
//modification won't alter publish date.
var p = listViewObject.properties;
return p.publishDate;
};
/*
* get the modified date for the workflow version, overwrite OOB since that uses last major version
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemUpdatedModifiedDate = function (p,listViewObject) {
var xmlDoc = listViewObject.getXmlDocument();
var modDate = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:RevisionDate");
return modDate;
}
/*
* Gets the updated Version information from the item
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemUpdatedVersion = function (p,listViewObject) {
var p = listViewObject.properties;
var xmlDoc = listViewObject.getXmlDocument();
var newVersionString = undefined;
if (xmlDoc) {
newVersionString = String.format("{0}.{1}", $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:Version"), $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:Revision"));
}
if (newVersionString != undefined) {
//want to ensure we're getting a LATER version than we had (because it will try to load the non-workflow version afterwards...
var iResult = newVersionString.localeCompare(p.previousVersion);
if (p.previousVersion === undefined || iResult > 0) {
p.versionNumberString = newVersionString;
} else {
p.versionNumberString = p.previousVersion;
}
} else {
p.versionNumberString = p.previousVersion;
}
return p.versionNumberString;
};
function launchPopup(winURL, winName, winFeatures, winObj) {
// this will hold our opened window
var theWin;
// first check to see if the window already exists
if (winObj != null) {
// the window has already been created, but did the user close it?
// if so, then reopen it. Otherwise make it the active window.
if (!winObj.closed) {
winObj.focus();
return winObj;
}
// otherwise fall through to the code below to re-open the window
}
// if we get here, then the window hasn't been created yet, or it
// was closed by the user.
theWin = window.open(winURL, winName, winFeatures);
return theWin;
}
var $extUtils = MyCompany.Tridion.RTFExtensions.Utilities;
Source: (StackOverflow)
I have a collection of checkboxes with generated ids and some of them have an extra attribute. Is it possible to use JQuery to check if an element has a specific attribute?
For example, can I verify if the following element has the attribute "myattr"? The value of the attribute can vary.
<input type="checkbox" id="A" myattr="val_attr">A</input>
For example how can I get a collection of all checkboxes that have this attribute without checking one by one? Is this possible?
Source: (StackOverflow)
In Java, what's the difference between:
private final static int NUMBER = 10;
and
private final int NUMBER = 10;
Both are private
and final
, the difference is the static
attribute.
What's better? And why?
Source: (StackOverflow)
Do you know if there is a built-in function to build a dictionary from an arbitrary object? I'd like to do something like this:
>>> class Foo:
... bar = 'hello'
... baz = 'world'
...
>>> f = Foo()
>>> props(f)
{ 'bar' : 'hello', 'baz' : 'world' }
NOTE: It should not include methods. Only fields.
Thanks
Source: (StackOverflow)
I want to create a dynamic object (inside another object) in Python and then add attributes to it.
I tried:
obj = someobject
obj.a = object()
setattr(obj.a, 'somefield', 'somevalue')
but this didn't work.
Any ideas?
edit:
I am setting the attributes from a for
loop which loops through a list of values, e.g.
params = ['attr1', 'attr2', 'attr3']
obj = someobject
obj.a = object()
for p in params:
obj.a.p # where p comes from for loop variable
In the above example I would get obj.a.attr1
, obj.a.attr2
, obj.a.attr3
.
I used the setattr
function because I didn't know how to do obj.a.NAME
from a for
loop.
How would I set the attribute based on the value of p
in the example above?
Source: (StackOverflow)
Possible Duplicate:
Finding an enum value by its Description Attribute
I have a generic extension method which gets the Description
attribute from an Enum
:
enum Animal
{
[Description("")]
NotSet = 0,
[Description("Giant Panda")]
GiantPanda = 1,
[Description("Lesser Spotted Anteater")]
LesserSpottedAnteater = 2
}
public static string GetDescription(this Enum value)
{
FieldInfo field = value.GetType().GetField(value.ToString());
DescriptionAttribute attribute
= Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute))
as DescriptionAttribute;
return attribute == null ? value.ToString() : attribute.Description;
}
so I can do...
string myAnimal = Animal.GiantPanda.GetDescription(); // = "Giant Panda"
now, I'm trying to work out the equivalent function in the other direction, something like...
Animal a = (Animal)Enum.GetValueFromDescription("Giant Panda", typeof(Animal));
Source: (StackOverflow)