This is my code for print: "url = ("https://etherscan.io/address/%s"address)" and i got SyntaxError: invalid syntax  My Python version is 3.7 and i'm new to python I think %s is the problem, i'm not what replacement of that in Python 3.7
I want to do something like String.Format("[{0}, {1}, {2}]", 1, 2, 3) which returns:  [1, 2, 3]   How do I do this in Python?
Why the Galaxy has 25GB instead of 32GB I just purchased a Samsung Galaxy S3 32GB, when I check the storage I have only 25.5GB. Where is the other 6.5GB? What is the difference between the following class methods?  Is it that one is static and the other is not?  class Test(object):   def method_one(self):     print "Called method_one"    def method_two():     print "Called method_two"  a_test = Test() a_test.method_one() a_test.method_two() Apache 2.4 - 403 HTTP status code In "", Mark Lutz mentions "mixins". I'm from a C/C++/C# background and I have not heard the term before. What is a mixin?   Reading between the lines of  (which I've linked to because it's quite long), I'm presuming it's a case of using multiple inheritance to extend a class as opposed to 'proper' subclassing. Is this right?   Why would I want to do that rather than put the new functionality into a subclass? For that matter, why would a mixin/multiple inheritance approach be better than using composition?  What separates a mixin from multiple inheritance? Is it just a matter of semantics? How to determine which app is causing vibration? I have a Moto G6 Play that vibrates like it is getting notifications but it's not. The vibration is inconsistent and seems random so I would like to know if there is a logcat or something I can run to log which app is calling the vibration so that I can shut it off? The same thing happens on my wife's phone, same model, and it does my head in. The device is running Android 9. Find the limit if it exists of $S_{n+1} = \frac{1}{2}(S_n +\frac{A}{S_n})$ Convert integers to written numbers Is there an efficient method of converting an integer into the written numbers, for example:  string Written = IntegerToWritten(21);   would return "Twenty One".  Is there any way of doing this that doesn't involve a massive look-up table? Here comes Bob.  Bob is coming here.  Would anyone please explain what is  the difference between these? It's a standard result that given $X_1,\cdots ,X_n $ random sample from $N(\mu,\sigma^2)$, the random variable $$\frac{(n-1)S^2}{\sigma^2}$$ has a chi-square distribution with $(n-1)$ degrees of freedom, where $$S^2=\frac{1}{n-1}\sum^{n}_{i=1}(X_i-\bar{X})^2.$$ I would like help in proving the above result. Thanks. Foreign key constraint on array member? Suppose I have a table containing job roles:  CREATE TABLE roles (   "role" character varying(80) NOT NULL,   CONSTRAINT "role" PRIMARY KEY (role) );   Suppose I further have a table, users, and each row (a specific user) can have an arbitrary number of job roles:  CREATE TABLE users (   username character varying(12) NOT NULL,   roles character varying(80)[] NOT NULL,   CONSTRAINT username PRIMARY KEY (username) );   I should probably make sure that each member of users.roles[] exists in roles.role.  It seems to me that what I want is a foreign key constraint on each member of users.roles[] such that if references roles.role.  This doesn't seem possible with postgres.  Am I looking at this the wrong way?  What is the suggested "right" way to handle this? I have recently been reading a lot on this site (@Aniko, @Dikran Marsupial, @Erik) and elsewhere about the problem of overfitting occuring with cross validation - (Smialowski et al 2010 Bioinformatics, Hastie, Elements of statistical learning).  The suggestion is that any supervised feature selection (using correlation with class labels) performed outside of the model performance estimation using cross validation (or other model estimating method such as bootstrapping) may result in overfitting.   This seems unintuitive to me - surely if you select a feature set and then evaluate your model using only the selected features using cross validation, then you are getting an unbiased estimate of generalized model performance on those features (this assumes the sample under study are representive of the populatation)?  With this procedure one cannot of course claim an optimal feature set but can one report the performance of the selected feature set on unseen data as valid?  I accept that selecting features based on the entire data set may resuts in some data leakage between test and train sets. But if the feature set is static after initial selection, and no other tuning is being done, surely it is valid to report the cross-validated performance metrics?   In my case I have 56 features and 259 cases and so #cases > #features. The features are derived from sensor data.  Apologies if my question seems derivative but this seems an important point to clarify.  Edit: On implementing feature selection within cross validation on the data set detailed above (thanks to the answers below), I can confirm that selecting features prior to cross-validation in this data set introduced a significant bias. This bias/overfitting was greatest when doing so for a 3-class formulation, compared to as 2-class formulation.  I think the fact that I used stepwise regression for feature selection increased this overfitting; for comparison purposes, on a different but related data set I compared a sequential forward feature selection routine performed prior to cross-validation against results I had previously obtained with feature selection within CV. The results between both methods did not differ dramatically. This may mean that stepwise regression is more prone to overfitting than sequential FS or may be a quirk of this data set. Can one do the maths of physics without using $\sqrt{-1}$? The use of imaginary and complex values comes up in many physics and engineering derivations. I have a question about that: Is the use of complex numbers simply to make the process of derivation easier, or is it an essential ingredient, without which it would be impossible to derive some results?   I can identify two different settings where the answer may be different:   It doesn't look like it is mandatory for results in Newtonian mechanics, General Relativity and classical electrodynamics. Can we say the same thing about quantum mechanics either way for sure?   Could this be a difference in quantum mechanics over the classical picture? Find hypotenuse given acute angle bisectors In a right triangle $ABC$ (right-angled at $B$), $D$ and $E$ are points of $\overline{AB}$ and $\overline{BC}$ respectively such that $\overline{CD}$ and $\overline{AE}$ are the angle bisectors of the acute angles of the triangle. Given that $AE=9$ and $CD=8\sqrt{2}$, find the length of the hypotenuse $\overline{AC}$. On finding polynomials that approximate a function and its derivative (extensions of Stone-Weierstrass?) Re-install Ubuntu without losing data in home folder Recently I installed Ubuntu 12.10 x64 Server Edition on my PC. Unfortunately, I attempted to install a lightweight desktop but due to the fact that I have an old graphics card, the PC does not perform so well. I am thinking of re-installing an Ubuntu version but I do not want to lose the contents in my home folder. Is there any way to do that with a Live CD? When I ordered this TP-Link AC1300 Wireless Dual Band PCI-Express Adapter (Archer T6E), I looked into customers reviews and they said it worked fine with no drivers on Ubuntu. I didn't have a CD/DVD player on my desktop so I (on a laptop with a DVD drive) copied and pasted the DVD support disk content on to a USB drive and used that. But when I tried to run autorun.exe it puts up archive manager and says An error occurred while loading the archive Ubuntu verison- Ubuntu 16.04 LTS.  Output from: lspci -vnn  02:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 11) Subsystem: ASRock Incorporation Motherboard (one of many) [1849:8168] Kernel driver in use: r8169  Kernel modules: r8169   I am fairly new to Ubuntu (1 month) and have learned alot (sudo commands) and now know that windows is overpriced and that ubuntu is better in most fields.  Thanks for the help. Integral of $\sin x \cos x$ using two methods differs by a constant? $$ \int \sin \theta\cos \theta~d \theta= \int \frac {1} 2  \sin 2\theta~ d \theta=-\frac {1} 4  \cos 2\theta$$ But, if I let  $$ u=\sin \theta , \text{ then }du=\cos \theta~d\theta $$ Then $$ \int \sin \theta\cos \theta~d \theta= \int u ~ du =\frac { u^2 } 2 =\frac {1} 2 \sin^2 \theta $$ Since $$ \sin^2 \theta =\frac {1} 2 - \frac {1} 2 \cos 2\theta$$ The above can be written as $$ \int \sin \theta\cos \theta~d \theta= \frac {1} 2 \sin^2 \theta =\frac {1} 2 \left( \frac {1} 2 - \frac {1} 2 \cos 2\theta \right)=\frac {1} 4-\frac {1} 4 \cos 2\theta   $$ Why are the two results differ by the constant $1/4$? Thank you. What rules say that summoning undead is evil, and what rules say why? After update, get "error: file not found." followed by "grub rescue> _" How does Fermat's principle make light choose a straight path over a short path? This is a thought experiment where I have made a &quot;C&quot; shaped hole inside diamond. The refractive index $(\mu)$ of diamond is 2.45. Say we shine a laser from top of the &quot;C&quot; as shown. My calculations show that light reaching A can reach B in the least possible time if gone through the &quot;C&quot;. but I'm pretty sure the perpendicular laser beam travels undeflected and straight down. Though I don't have experimental evidence, I see something wrong either with my intuition or with the theory. It would be great if someone could clarify. *       'a' in the diagram is the thickness of the cutout and all comparable distances can be taken 'a'.