I am working with regular expressions and am struggling to understand a particular output.  Case 1:  &gt;&gt;&gt; m = re.match("(abc)+", "abc") &gt;&gt;&gt; m.groups() ('abc',)   Case 2:  &gt;&gt;&gt; m = re.match("([abc])+", "abc") &gt;&gt;&gt; m.groups() ('c',)   In Case 1 above, I do understand how m.groups() returns ('abc',) (a tuple with the matched string for group 1, the only group in the RE).  However, in Case 2 above, where I put 'abc' in the RE inside a character class as [abc], I do not understand why does m.groups() return ('c',). I would have still expected the same tuple returned as Case 1, i.e. ('abc',)  Could anyone please help me understand why does m.groups() return ('c',) in Case 2.
I have a Python regular expression that contains a group which can occur zero or many times - but when I retrieve the list of groups afterwards, only the last one is present. Example:  re.search("(\w)*", "abcdefg").groups()  this returns the list ('g',)  I need it to return ('a','b','c','d','e','f','g',)  Is that possible? How can I do it?
undefined control sequence when using \addchap When I compile my thesis.tex file which is compiled fine including the \addchap, I noticed that I have used \usepackage{unnumberedtotoc}. When I want to use my thesis.tex file on another computer it says tex capacity exceeded, sorry [input stack size=5000]. When I uncomment \usepackage{unnumberedtotoc}, it says ! undefined control sequence  \addchap.  Here I have pasted all the beginning of the packages that I have used in my thesis but I still get some problems in compilation, I don't know why, but I think if I can compile this code, then I can solve the problem  :   \immediate\write18{makeindex \jobname.nlo -s nomencl.ist -o \jobname.nls} \documentclass[12pt]{report} \DeclareMathSizes{12}{30}{16}{12} \usepackage[utf8]{inputenc} \usepackage{graphicx} \usepackage{lineno} \usepackage{amsmath}  \usepackage{array, nccmath}  \usepackage[nottoc]{tocbibind} \newcolumntype{L}{&gt;{$}l&lt;{$}} \newcolumntype{m}{&gt;{\displaystyle}l} \usepackage{framed} \usepackage{cclicenses} \usepackage{makecell} \usepackage[french]{babel} \usepackage{setspace} \usepackage{mathptmx}  \usepackage{multirow}  \usepackage{gensymb}  \usepackage{empheq}   \usepackage{mathtools}   \usepackage{array}   \renewcommand{\arraystretch}{1.9}   \newcolumntype{P}{&gt;{\centering\arraybackslash$}p{1.6em}&lt;{$}}   \newcolumntype{C}{&gt;{\centering\arraybackslash$}c&lt;{$}}   \usepackage{makecell}   \usepackage{booktabs}   \usepackage{subcaption}   \usepackage[intoc]{nomencl}   \makenomenclature   \setcounter{secnumdepth}{4}   \setcounter{tocdepth}{4}   \usepackage[justification=centering]{caption}    \usepackage{etoolbox}     \usepackage{unnumberedtotoc} %https://github.com/johannesbottcher/unnumberedtotoc/     \usepackage[automark,     plainheadsepline,     headsepline,     plainfootsepline,      footsepline,     markcase=ignoreupper]{scrlayer-scrpage}    \clearpairofpagestyles    \ihead*{\leftmark}    \cfoot*{\pagemark}    \setkomafont{pageheadfoot}{\scshape}    \usepackage{titlesec}    \graphicspath{{imagesthesis/}}    \def\frenchlistfigurename{Liste des figures}    \usepackage[a4paper,right=20mm,left=25mm,top=26mm, bottom=26mm]{geometry}    \makeatletter    \titleformat{\chapter}[display]    {\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge}    % this alters "before" spacing (the second length argument) to 0    \titlespacing*{\chapter}{0pt}{0pt}{20pt}    %\patchcmd{\@makechapterhead}{\vspace*{20\p@}}{}{}{}% Removes space above \chapter head    %\patchcmd{\@makeschapterhead}{\vspace*{20\p@}}{}{}{}% Removes space above \chapter* head    \makeatother    \title {itle of the thesis}    \titleformat{\paragraph}    {\normalfont\normalsize\bfseries}{\theparagraph}{1em}{}    \titlespacing*{\paragraph}     {0pt}{3.25ex plus 1ex minus .2ex}{1.5ex plus .2ex}     \usepackage[thin, , thinc]{esdiff}  \usepackage{subcaption}  \usepackage{caption}  \usepackage{framed}    \usepackage{nomencl}   \setlength{\nomitemsep}{-\parskip}\usepackage{booktabs,multirow}  \renewcommand{\cellset}{\renewcommand{\arraystretch}{0.5}}   \begin{document}  \renewcommand\arraystretch{0.8} %\noindent  \doublespacing  \maketitle  \tableofcontents %\listoffigures  \addchap{Publications et communications}   \section*{$\:$  a. Publications:}  \section*{$\:$  b. Communications:}  \addchap{Remerciements}  \end{document} When is it correct to use the "-wise" suffix? Let $(X,d)$ be a metric space and let $S$ be the set of Cauchy sequences in $S$. Define "~" in $S$ by "$\{s_k\}$ ~ $\{t_k\}$" to mean that $d(s_k,t_k) \to 0$ as $k \to \infty$. Let $X'$ denote the set of equivalence classes of $S$ and let $s'$ denote the equivalence class of $s = \{s_k\}$.   I know $\phi(s',t') = \lim\limits_{k \to \infty} d(s_k,t_k)$ is a metric on $X'$.   Show $(X',\phi)$ is complete.  For $x \in X$, define $x'$ to be the equivalence class of the constant sequence ${x,x,...}$. Show that the function $x \to x'$ is an isometry of $X$ onto a dense subset of $X$.   If anyone can share a proof, or steer me in the right direction, maybe tell me what it is that I need to prove specifically, that would be great. Calculating centroids of polygon using ArcPy? I am trying to calculate the centroids of a polygon and add the x- and y-coordinate to their respective fields:  arcpy.env.workspace = r"C:/..."  input_fc = "shapefiles/precincts_v.shp" arcpy.AddField_management(input_fc, "X", "DOUBLE") arcpy.AddField_management(input_fc, "Y", "DOUBLE")  arcpy.CalculateField_management(input_fc, "X", "!SHAPE.CENTROID@DECIMALDEGREES!.split()[0]", "PYTHON")  arcpy.CalculateField_management(input_fc, "Y", "!SHAPE.CENTROID@DECIMALDEGREES!.split()[1]", "PYTHON")    but I an invalid syntax error. Where is the mistake?  Edit: exact error message  Traceback (most recent call last):   File "C:\Users\mquentel\Dropbox\PLSS\CA voting data\Python\CONSTRUCT_merge_voting_and_census.py", line 17, in &lt;module&gt;     arcpy.CalculateField_management(input_fc, "X", "!SHAPE.CENTROID@DECIMALDEGREES!.split()[0]", "PYTHON")   File "C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy\arcpy\management.py", line 3360, in CalculateField     raise e ExecuteError: ERROR 000539: SyntaxError: invalid syntax (&lt;expression&gt;, line 1) Failed to execute (CalculateField). Having links relative to root? Is it possible to reintegrate a Horcrux? As anyone who is familiar with Harry Potter knows, a horcrux is made when someone commits murder and stores a piece of their soul in something. Would it be possible for this someone to later recover and reintegrate their soul piece(s), should they want to? Finding singularities of a complex function and the respective residues Consider the function,   $$f(z) = \frac{\sin(\frac{1}{z})}{z^2+a^2} \text{ where } a&gt;0$$  I know that this has two simple poles at $z = \pm ia$ and an essential singularity at $z = 0$ because of $\sin(\frac{1}{z})$ in the numerator. For $\operatorname{Res}(f,ia)$ and $\operatorname{Res}(f,-ia)$, it is relatively easy to find the these values using   $$a_{-1} = \lim_{z\rightarrow z_0} ((z-z_0)f(z))$$  However, I am finding it much more difficult to determine the residue at an essential singularity.  From what I have read, it seems that the easiest way to determine the residue is to explicitly find the Laurent Expansion and then get it from there. Would this be the case for this function as well? Prove that $(p+q)^m \leq p^m+q^m$ Lost USB BlueTooth Dongle for Keyboard and Mouse I lost my USB bluetooth dongle (from HP) which I used for a wireless keyboard and mouse. They came together in a set when I bought my last HP computer.  Are the keyboard and mouse useless now? or will any bluetooth dongle allow them to work? If I can just buy a new one - any recommendations on a replacement (good price, and perhaps works with Windows and Ubuntu out-of-the-box?   Forgive me if this is an easy question. I'm just not that familiar with wireless mice/keyboards. Opening Chromium on Ubuntu VPS Ubuntu noob here. I recently got a VPS running Ubuntu, and decided to install Chromium, my preferred browser, on it. After installation completed, I got a message stating that I cannot open Chromium with root privileges. How would I go about opening Chromium? Calculating $\lim_{n\to\infty}\sqrt[n]{2^n-n^2}$ Router to router setup works fine with straight cable up to 2-3 meter it is not working for 45 meter why? Does lower resolution result in better signal-to-noise ratio, given the same sensor size? With the release of the Canon EOS R5/R6, there have been many saying that they prefer the 20MP R6 camera over the 45MP R5 camera, due to its lower price but also because of &quot;better low-light performance.&quot; In camera comparison sites, I've also seen the sentiment that bigger pixels (lower resolution) = better low light performance. However, is this a myth? Here is my reasoning for this. Let's say that there are two full-frame sensors, one 20MP sensor and a 80MP sensor. According to many people, the 80MP sensor would be terrible for low-light photography since the pixels are smaller. However, each 2x2 block in the 80MP sensor could be mapped, and in post averaged to a 1x1 pixel, effectively making the image into a 20MP image. This could also be done in-camera as an option. Would this image have just the same amount of usable information as the image from the 20MP sensor? In other terms, since both sensors are 35mm sensors (i.e. equal area), the amount of light falling onto the sensor is the same. So, at the end of the day, there will be no difference between a 20MP image and a 20MP image that has been downsampled from 80MP, right? So their low-light performance would be the same. You even get an advantage from having the option to get 80MP photos if you wanted. Why do people say that a lower-resolution camera has better low-light performance, when it should theoretically be the same as one with higher resolution (all other factors equal)? Note: this question is about sensors with the same size but with different pixel density. Hence, it is different from  asking about different sensor sizes. I am aware that a full-frame camera will have better low-light signal due to its bigger area than an APS-C sensor, but what about the similarly sized sensors? Bluetooth earphones work fine until sleep. After resuming from sleep however, they appear to connect for a brief moment before disconnecting. On blueman, the error given is Resource temporarily unavailable. This issue arose only after updating to 18.04 LTS.   Here's the terminal output for lsusb:  Bus 001 Device 002: ID 8087:8001 Intel Corp.  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002 Device 004: ID 1bcf:0002 Sunplus Innovation Technology Inc.  Bus 002 Device 003: ID 04f2:b477 Chicony Electronics Co., Ltd  Bus 002 Device 002: ID 0a5c:21f1 Broadcom Corp. HP Portable Bumble Bee Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Evaluate $\int_0^{\infty}\frac{\log x}{1+e^x}\,dx$ How can a file be copied? Does a non-trivial solution exist for $f'(x)=f(f(x))$? I have the following code:  if ($_POST['submit'] == "Next") {     foreach($_POST['info'] as $key =&gt; $value) {         echo $value;     } }   How do I get the foreach function to start from the 2nd key in the array? How to load a taxonomy term with case-sensitive? I used this      $this-&gt;termStorage-&gt;loadByProperties(['name' =&gt; 'test']);   I got two terms: Test, test. I want to get only one: test  This is working without case-sensitive:       $this-&gt;termStorage-&gt;getQuery()-&gt;condition('name', 'test', '=')-&gt;execute();       \Drupal::database()-&gt;select('taxonomy_term_field_data', 't')       -&gt;condition('t.name', 'test')       -&gt;fields('t', ['name'])       -&gt;execute()       -&gt;fetchAll();       \Drupal::database()-&gt;query("SELECT name FROM taxonomy_term_field_data WHERE name='test'")-&gt;fetchAll(); Strange black shading. Cannot fully light mesh. (Cycles)