Property decorators are discussed at length in the documentation and the machinery which resolves them is discussed as well, but only for getters. I have been entirely unsuccessful in making a setter work for an uninstantiated class. Simple example:  My Property Decorator  class ClassyProp(object):      """ Classmethod + property """      def __init__(self, input_func):         log(f"ClassProp.__init__({input_func})")         self.func = input_func      def __get__(self, obj, cls=None):         log(f"ClassProp.__get__({obj}, {cls})")         return self.func      def __set__(self, obj, value):         log("__ClassyProp__.__set__()")      def setter(self, fset):         log("__ClassyProp__.setter()")      def fset(*args):         log("__ClassyProp__.fset()")   Test Class  class foo(object):     """ Test class """      def __init__(self):         pass      @ClassyProp     def f(cls):         """ Test property_lazy_static get , set """         pass   Run  print("======== ObjFoo ========")  ObjFoo = foo() print(ObjFoo.f) ObjFoo.f = 18 print(ObjFoo.f)  print("======== class foo ========")  print(foo.f) foo.f = 15 print(foo.f)   Yields  [      00s] ClassProp.__init__(&lt;function foo.f at 0x7f4330c88268&gt;) ======== ObjFoo ======== [      00s] ClassProp.__get__(&lt;__main__.foo object at 0x7f4351522748&gt;, &lt;class '__main__.foo'&gt;) &lt;function foo.f at 0x7f4330c88268&gt; [      00s] __ClassyProp__.__set__() [      00s] ClassProp.__get__(&lt;__main__.foo object at 0x7f4351522748&gt;, &lt;class '__main__.foo'&gt;) &lt;function foo.f at 0x7f4330c88268&gt; ======== class foo ======== [      00s] ClassProp.__get__(None, &lt;class '__main__.foo'&gt;) &lt;function foo.f at 0x7f4330c88268&gt; 15   NOTE: If I had ClassyProp return values it wouldn't say the function id, does say proper values for get, but I just wanted print outs for the purpose of debugging.  As you can see, the getter AND setter is called properly for the Instance of ObjFoo. But not for the uninstantiated class foo. Is having a property setter simply not possible on classes? The documentation states (I added breaks):     For objects, the machinery is in    - object.getattribute() which transforms b.x into    - type(b).dict['x'].get(b, type(b))        The implementation works through a precedence chain that    - gives data descriptors priority over instance variables,    - instance variables priority over non-data descriptors, and    - assigns lowest priority to getattr() if provided.     and     For classes, the machinery is in:      - type.getattribute() which transforms B.x into      - B.dict['x'].get(None, B)     With no mention of __set__ for either. (get obviously is working for both the class and the instance)  So I am left wondering now, is this possible? I see nothing in the documentation suggesting it isn't, but all testing suggests this.
I have a class with two class methods (using the classmethod() function) for getting and setting what is essentially a static variable.  I tried to use the property() function with these, but it results in an error.  I was able to reproduce the error with the following in the interpreter: class Foo(object):     _var = 5     @classmethod     def getvar(cls):         return cls._var     @classmethod     def setvar(cls, value):         cls._var = value     var = property(getvar, setvar)  I can demonstrate the class methods, but they don't work as properties: &gt;&gt;&gt; f = Foo() &gt;&gt;&gt; f.getvar() 5 &gt;&gt;&gt; f.setvar(4) &gt;&gt;&gt; f.getvar() 4 &gt;&gt;&gt; f.var Traceback (most recent call last):   File &quot;&lt;stdin&gt;&quot;, line 1, in ? TypeError: 'classmethod' object is not callable &gt;&gt;&gt; f.var=5 Traceback (most recent call last):   File &quot;&lt;stdin&gt;&quot;, line 1, in ? TypeError: 'classmethod' object is not callable  Is it possible to use the property() function with @classmethod decorated functions?
Asking the position of a person in a sequence How to ask the position(?) of a president (like 10th) of a country, correctly? Frequency count of two column in R The question is from Axler's "Linear Algebra Done Right", which I'm using for self-study.  We are given a linear operator $T$ over a finite dimensional vector space $V$. We have to show that $T$ is a scalar multiple of the identity iff $\forall S \in {\cal L}(V), TS = ST$. Here, ${\cal L}(V)$ denotes the set of all linear operators over $V$.  One direction is easy to prove. If $T$ is a scalar multiple of the identity, then there exists a scalar $a$ such that $Tv = av$, $\forall v \in V$. Hence, given an arbitrary vector $w$, $$TS(w) = T(Sw) = a(Sw) = S(aw) = S(Tw) = ST(w)$$ where the third equality is possible because $S$ is a linear operator. Then, it follows that $TS = ST$, as required.  I am, however, at a loss as to how to tackle the other direction. I thought that a proof by contradiction,  ultimately constructing a linear operator $S$ for which $TS \neq ST$, might be the way to go, but haven't made much progress.   Thanks in advance! Note that (1) all norms on finite dimensional vector space are equivalent.  And here (2) norms on vector space are equivalent iff they have same topology.   Question : How can we prove (2) ? Please recommend reference  Thank you in anticipation How can I find $\lim_{n\to \infty} a_n$ Let $$a_n=\left(1-\dfrac{1}{\sqrt2}\right)\dots \left(1-\dfrac{1}{\sqrt{n+1}}\right),n\ge1$$ Then find $\lim_{n\to \infty} a_n$.   How can I proceed? I am stuck at the first step. Please help. All of a sudden, without any change in the index.html, our site is showing up in Google search results (on multiple browsers and devices) with Google Preview text that, instead of giving a summary of our site, now says:     Your browser does not currently recognize any of the video formats available. Click here to visit our frequently asked questions about HTML5 video.     We have a YouTube embed on our homepage that does include an html5 parameter in the media URL link in the embed, but there are no issues playing the video with any browser and device we can find.  What would suddenly cause this text to appear in Google search results?   We are using the  tags as the metatags in the &lt;head&gt; of our webpage and do indeed have title and description tags.    To mimic the behavior of Googlebot, I installed Windows on a VM and got Chromium 41 running. I get the same Google Preview text with the html5 video message when the site comes up in Google search results using this browser.    When I view the site in Chromium 41, I see the YouTube embed and it renders on the page and plays with no issue, just as with all other browser and devices we've tested on. The only time we see this message is in the Google search results, not on our actual site. Creating Two Executable Jars Using maven-assembly-plugin Atheros AR9462 WiFI very unstable & package loss I'm having severe issues w/ package-loss and a generally bad connection w/in a WiFi-network at my uni. I'm usually encountering a package loss of ~50% and aborting connections which makes working w/ SaaS impossible.  I'm using Ubuntu 13.04 and my network-adapter is an Atheros AR9462.  Applying the nohwcrypt=1-option doesn't change anything.  Also very noticable: The connection works as intended in other networks; the problematic network uses WPA2 w/ MSCHAPv2.  Anyone can help my out here?  $ sudo lshw -class network  *-network UNCLAIMED             description: Ethernet controller        product: NetLink BCM57780 Gigabit Ethernet PCIe        vendor: Broadcom Corporation        physical id: 0        bus info: pci@0000:04:00.0        version: 01        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: memory:d3500000-d350ffff   *-network        description: Wireless interface        product: AR9462 Wireless Network Adapter        vendor: Atheros Communications Inc.        physical id: 0        bus info: pci@0000:09:00.0        logical name: wlan0        version: 01        serial: e0:06:e6:76:ba:89        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless        configuration: broadcast=yes driver=ath9k driverversion=3.8.0-22-generic firmware=N/A ip=131.173.74.130 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn        resources: irq:19 memory:d3400000-d347ffff memory:9fb00000-9fb0ffff Natbib In-Text Citation displays (author?) Why aren't these loops homotopic? Let $S^1 = \{z \in \mathbb{C} : |z| = 1\}$.  Take the loops $f,g : [0,1] \rightarrow S^1$, $f(t) = 1$, $g(t) = e^{2\pi it}$.  I know these represent different elements in $\pi_1(S^1, 1)$, but I don't see why $F(t,s) = e^{2\pi its}$ isn't a homotopy between $f$ and $g$. Where, how and when I can acquire HM's? Apex:OutputText to Currency Format from String Wrapper is there a way to pass a string to the &lt;apex:outputText&gt; so that it can be formatted as a currency or percent value?  Here's what I have inside a column of my visual force table:  &lt;apex:outputText value="{0, number, currecny}"&gt; &lt;apex:param value="{!row.values[1]}" /&gt; &lt;/apex:outputText   this gives me an error at runtime (when the visual force page loads), which I think may be some kind of type mismatch, where &lt;apex:outputText&gt; is expecting a Decimal or number but I am passing a string.  This is the error at runtime:     The value attribute on  is not in a valid format. It must be a positive number, and of type Number, Date, Time, or Choice.   Thanks Get display resolution from the command line for Linux Desktop I'm looking for a method of reporting display resolution. I want to set up scripts to launch rdesktop, and I want to launch it on several machines with different resolutions, so I want a way to dynamically determine it. Need to delete a directory with name '~' created accidentally Can you grab the blue shirts and socks?   Is the above sentence stating that both the shirts and the socks are blue? Or only the shirts?  At this stage, I am leaning towards the earlier (only the shirts) — though writing "Can you grab the blue shirts and blue socks?" seems redundant. The 's  feature (E:RftLW, p. 58; WGtE, p. 180) states:     [...] You ignore all class, race, spell, and level requirements on attuning to or using magic items.   Class and race requirements are relatively intuitive, additionally, since an Artificer is able to cast spells they can already attune to items that require you to be a spellcaster. But there's still some questions:   Can they use a spell scroll of a spell not on their spell list? Is this one of the four requirements ignored? What are level and spell requirements; what are some examples? Reporting Mann-Whitney U-Test without homogenity of variance The Mann-Whitney test requires homogeneity of variance if a median difference is suppossed to be statistically significant.  In case homogenity of variance is not met, but the test is significant:  Which aspects of the test can I report? How to make DNS server propagate faster if you are a site owner? I used a website called Seeking Arrangements and met a  sugar daddy. He asked for my email login, online banking login, routing, account number, Facebook, as well as my  address which is the only thing I gave him since it’s a PO. I’ve been extremely vague just to see if this is real.   I don’t plan to give him anything because I have only been talking to him for a few months and  I feel conflicted. I doubt that he is trying to scam me but I suspect that he has some kind of master plan. With things such as Venmo, Zelle, and Cashapp, what is the need for “put me on his payroll?”   He claims that he is in another country on a business trip.  He said that  he tried to send me a gift but he lost access to his card. He is now asking to deposit more than 10k into my account and have me wire it. Is this a l classic way of scamming people? If so, is it common that they spend months creating a relationship with you  to catfish you? if m varies then find the range of c for which the line $y=mx + c$ touches the parabola $y^2 = 8(x+2)$ .  I tried Put the value $y = mx + c in$ the parabola equation and then done $D = 0$ or $D&gt;0 $  I am getting $16/(m^2 + 8m) &gt;0 $  But in this , how do I neglect m