I'm trying to change the value of one cell in a 2D python array:  [[0, 1, 2], [0, 1, 2], [0, 1, 2]]   which I generated from  m=3*[[0]*3] for y in xrange(0,3):     for x in xrange(0,3):         m[y][x]=x   I want to replace m[0][0] with 5 so that it looks like  [[5, 1, 2], [0, 1, 2], [0, 1, 2]]   but instead it is  [[5, 1, 2], [5, 1, 2], [5, 1, 2]]   when i use   m[0][0]=5   what's going on?
I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?
A stochastic process is a process that evolves over time, so is it really a fancier way of saying "time series"? Let $X$ be any distribution with defined mean, $\mu$, and standard deviation, $\sigma$.  The central limit theorem says that  $$ \sqrt{n}\frac{\bar{X} - \mu}{\sigma}  $$ converges in distribution to a standard normal distribution.  If we replace $\sigma$ by the sample standard deviation $S$, is there a theorem stating that  $$ \sqrt{n}\frac{\bar{X} - \mu}{S}  $$ converges in distribution to a t-distribution?  Since for large $n$ a t-distribution approaches a normal, the theorem, if it exists, may state that the limit is a standard normal distribution.  Hence, it would seem to me that t-distributions are not very useful - that they are useful only when $X$ is roughly a normal.  Is this the case?    If it is possible, would you indicate references that containing a proof of this CLT when $\sigma$ is replace by $S$?  Such a reference could preferably use measure theory concepts.  But anything would be great to me at this point. I have problems with getting an Asus PCE-N53 11n N600 PCI-E Adapter card to work on my desktop computer.  As far as I can tell no drivers are installed for the card. I know I can manually download the drivers directly from Asus, but I would rather not go that route.  If there are anyone that knows about any packages or other things I can do to make this work would be much appreciated.  Some systems details:  $ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 12.04.1 LTS Release:    12.04 Codename:   precise   $ sudo lshw -C network   *-network                       description: Ethernet interface        product: RTL8111/8168B PCI Express Gigabit Ethernet controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:03:00.0        logical name: eth0        version: 06        serial: d4:3d:7e:03:b9:1d        size: 100Mbit/s        capacity: 1Gbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168e-3_0.0.4 03/27/12 ip=192.168.0.173 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s        resources: irq:43 ioport:d000(size=256) memory:f2104000-f2104fff memory:f2100000-f2103fff  *-network UNCLAIMED        description: Network controller        product: Ralink corp.        vendor: Ralink corp.        physical id: 0        bus info: pci@0000:04:00.0        version: 00        width: 32 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: memory:f7100000-f710ffff  $ lsmod Module                  Size  Used by nvidia              12319264  51  vesafb                 13844  1  snd_hda_codec_hdmi     32474  1  joydev                 17693  0  bnep                   18281  2  rfcomm                 47604  0  bluetooth             180104  10 bnep,rfcomm snd_hda_codec_realtek   224173  1  snd_seq_midi           13324  0  ppdev                  17113  0  snd_rawmidi            30748  1 snd_seq_midi usbhid                 47199  0  hid                    99559  1 usbhid nouveau               774641  0  parport_pc             32866  1  snd_hda_intel          33773  5  ttm                    76949  1 nouveau snd_hda_codec         127706  3 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel drm_kms_helper         46978  1 nouveau drm                   242038  3 nouveau,ttm,drm_kms_helper snd_seq_midi_event     14899  1 snd_seq_midi snd_hwdep              13668  1 snd_hda_codec snd_seq                61896  2 snd_seq_midi,snd_seq_midi_event i2c_algo_bit           13423  1 nouveau mxm_wmi                12979  1 nouveau wmi                    19256  1 mxm_wmi mac_hid                13253  0  snd_pcm                97188  3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec psmouse                97362  0  video                  19596  1 nouveau snd_timer              29990  2 snd_seq,snd_pcm snd_seq_device         14540  3 snd_seq_midi,snd_rawmidi,snd_seq snd                    78855  20 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_rawmidi,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_seq,snd_pcm,snd_timer,snd_seq_device serio_raw              13211  0  soundcore              15091  1 snd snd_page_alloc         18529  2 snd_hda_intel,snd_pcm mei                    41616  0  lp                     17799  0  parport                46562  3 ppdev,parport_pc,lp r8169                  62099  0 Is there a package that supports the addition or subtraction of chemical equations, perhaps with automatic tabbing and a alignment.  Whilst it is obvious I could set up tables or use mathmode's align feature, it seems so much more efficient to have a package handle the tabbing automatically, since it is rather predictable in this application.  mhchem does not seem to have such a feature...      Another advantage is you could maintain the readability of your equations and you would not have the added clutter associated with tables, especially tabs &amp;, which diminish the readability of your .tex document.  And of course, the line should be automatically inserted before the last row. Programming with Dynamic Find All Solutions to System of Congruence $$ \begin{cases} x\equiv 2 \pmod{3}\\ x\equiv 1 \pmod{4}\\ x\equiv 3 \pmod{5} \end{cases} $$  $ n_1=3\\ n_2=4\\ n_3=5\\ N=n_1 * n_2 * n_3 =60\\ m_1 = 60/3 = 20\\ m_2 = 60/4 = 15\\ m_3 = 60/5 = 12\\ gcd(20,3)=1=-20*1+3*7\\ gcd(15,4)=1=-15*1+4*4\\ gcd(12,5)=1=12*3-5*7\\ x=-20*2-15*1+12*3\equiv -19 \equiv 41 \pmod{60}\\ $  The above is what I've tried so far. Can someone tell me where I'm going wrong? It's my first time doing this and looking at the explanation and examples for the Chinese Remainder Theorem makes my head want to explode. Prove $[\sin x]' = \cos x$ without using $\lim\limits_{x\to 0}\frac{\sin x}{x} = 1$ I came across this question:   From the comments, Joren said:     L'Hopital Rule is easiest: $\displaystyle\lim_{x\to 0}\sin x = 0$ and $\displaystyle\lim_{x\to 0} = 0$, so $\displaystyle\lim_{x\to 0}\frac{\sin x}{x} = \lim_{x\to 0}\frac{\cos x}{1} = 1$.   Which Ilya readly answered:     I'm extremely curious how will you prove then that $[\sin x]' = \cos x$   My question:  is there a way of proving that $[\sin x]' = \cos x$ without using the limit $\displaystyle\lim_{x\to 0}\frac{\sin x}{x} = 1$. Also, without using anything else $E$ such that, the proof of $E$ uses the limit or $[\sin x]' = \cos x$.    All I want is to be able to use L'Hopital in $\displaystyle\lim_{x\to 0}\frac{\sin x}{x}$. And for this, $[\sin x]'$ has to be evaluated first.    Alright... the definition that some requested.   Def of sine and cosine: Have a unit circumference in the center of cartesian coordinates. Take a dot that belongs to the circumference. Your dot is $(x, y)$. It relates to the angle this way: $(\cos\theta, \sin\theta)$, such that if $\theta = 0$ then your dot is $(1, 0)$.  Basically, its a geometrical one. Feel free to use trigonometric identities as you want. They are all provable from geometry. I took this photo of the blood moon this morning and I am finding many of my photos, especially landscape photos, have a significant lack of clarity. I'm not looking for a photo critique because I know this particular photo is crap. I'm looking to identify my source of failure to nail a significantly clear photo.     Setup  Canon EOS 70D with a 100-300 telephoto lens (I'm sorry I don't know the exact model. It's from Canon but not one of their professional quality lenses.)   Aperture: f/5.6 Shutter: 1 sec. ISO: 1000 Focal Length: 300mm Metering mode: Spot White Balance: I manually set the WB to 5500 kelvin, it looked fine in live view. Focus Mode: Manual Drive: 2 sec timer delay   Mounted on a decently stable tripod  Process  I turn on live view, and square up the target in the display. I then set my focal length, focus in using live view, adjust the focus as sharp as possible and take the pic. I've noticed that in this case, the picture was incredibly grainy, which doesn't translate to the final photo, but wonder if it has anything to do with it.  This particular shoot I found it difficult to balance out the variables with a dark sky and a moving moon that starts blurring after 1-2 seconds of exposure, which is why I had the aperture wide open and the ISO cranked up.  I can't tell where I'm failing:  Equipment:  The 70d takes great photos but the telephoto is not great when it's totally zoomed in. My wallet doesn't hold enough cash for a motorized mount to track objects in the sky.  Circumstance: I've seen great photos of the moon with the use of a camera and a tripod, so I know this is possible. Although, I keep seeing pictures of this big gorgeous moon over the landscape, and when I use my wide-angle, the moon shows up as a dot. What the hell are people doing to get the moon so big?  Beginner skill level: I know this is the biggest culprit, but being the beginner, I'm unable to know where to adjust. Compute the sum of the series $\sum_{n=1}^{\infty} \frac{1}{n \cdot 2^n}$ What would be the sum of the following series?  $$\sum_{n=1}^{\infty} \frac{1}{n \cdot 2^n}$$  Thanks How to list all nodes of nodetype A which has the current node referenced? So this is what I'm trying to do in Drupal 6:  Node type A is video, node type B is a person Nodetype A has a reference field where you can enter a reference to any Node from nodetype B  how can I create a block view which will be displayed on nodes from node type b, which will show all the nodes from node type A where the current node from node type B is referenced? What is the difference between ubuntu-18.04-server and ubuntu-18.04-live-server? On the  there is a download link for ubuntu-18.04-live-server-amd64.iso, and on the  there is a download link for ubuntu-18.04-server-amd64.iso. Before 18.04, there is only a server version. What is the difference between these 2 images? How to change language of a specific application? Do Chinese citizens require a visa to go to Hong Kong for less than 7 days? How To Make A Solid Object Drop To The Ground Like It Was Liquid So I have a simple bouncing ball animation, but I just wanted to something "weird" for the ending. Is there a way to change the ball's material on the fly, where after the last bounce it changes materials and physical composition from a rigid body(baked animation now) to a fluid sim?  (within 30-40 frames) How to blacklist kernel modules? How do I disable loading of unnecessary kernel modules. Kernel 3.2.4 $AB-BA=I$ having no solutions Please help me to find elements $a,b$ in a ring $R$ such that $a\mid b$ and $b\mid a$, but there does not exist any unit $u$ in $R$ such that $a=ub$. Is it possible to call a non-exported function that resides in an exe? Ideals in ring of continuous functions $\mathcal{C}[0,1]$ ... NBHM- Algebra I would like to compile all questions I have encountered with Ideals in the ring $\mathcal{C}[0,1]$ of all continuous real valued functions and ask if there are any gaps.  Question is to see if :     the ideal $\mathcal{I}=\{f\in \mathcal{C}[0,1] : f(0)=0\}$ is maximal ideal in the ring $\mathcal{C}[0,1]$ of all continuous real valued functions.   What I have done so far is :  consider $\eta :\mathcal{C}[0,1]\rightarrow \mathbb{R}$ where $f\rightarrow f(0)$   $Ker (\eta) = \{ f\in \mathcal{C}[0,1] : f(0)=0\}$  I could see that for each $r\in \mathbb{R}$, I would set $f$ such that $f(x)=x+r$  So, $\eta$ is surjective.  So, I would get $\mathcal{C}[0,1]/\mathcal{I}\cong \mathbb{R}$  As $\mathbb{R}$ is a field so ia the quotient $\mathcal{C}[0,1]/\mathcal{I}$ which means that $\mathcal{I}$ is an ideal in $\mathcal{C}[0,1]$.    Now Another Question on same idea :  Question is to see if :     the ideal $\mathcal{I}=\{f\in \mathcal{C}[0,1] : f(0)=f(1)=0\}$ is maximal ideal in the ring $\mathcal{C}[0,1]$ of all continuous real valued functions.   I thought of using same ideas as above but i am unable to choose perfect $\eta$  I believe that this is not even a prime ideal..  I set  $f(x)=x$ and $g(x)=x-1$ and consider $f(x)g(x)=(x)(x-1)$ then,   $(fg)(0)=f(0)g(0)=0.(-1)=0$   $(fg)(1)=f(1)g(1)=1.0=0$  So, $fg\in \mathcal{I}=\{f\in \mathcal{C}[0,1] : f(0)=f(1)=0\}$ but the neither $f$ nor $g$ is in $\mathcal{I}$.    I have two questions:   I see that $0$ does not play any role in the question $\mathcal{I}=\{f\in \mathcal{C}[0,1] : f(0)=0\}$ I mean I would have same case if i replace $0$ by any real number.  So, I would like to say that $$\mathcal{I}=\{f\in \mathcal{C}[0,1] : f(r)=0\}$$  is a maximal ideal in the ring $\mathcal{C}[0,1]$ of all continuous real valued functions.  And one more thing I would claim is that      If the collection $\mathcal{I}$ is such that all elements of $\mathcal{I}$ has more than $1$ common zero then $\mathcal{I}$ is not a maximal ideal and not even a prime ideal..   I would like to learn more about this kind of ideals in $\mathcal{C}[0,1]$.  I would be thankful if some one can assure that what  have done is sufficient to conlcude what i have concluded and I would be thankful if some one can suggest some material to read regarding this.  Thank you The div containing tags for a question doesn't reflow, causing layout issues for questions with long/many tags This appears to be a css bug which (I think) has recently been introduced. It's most visible when viewing questions on Stack Exchange sites using mobile devices (the full site with responsiveness, not the mobile site) but can easily be reproduced by resizing a browser window on a question where the combined width of the tags is large. A couple of example questions show this behaviour:  On Meta Stack Overflow:   On Meta Stack Exchange:     Using the Meta Stack Overflow question to demonstrate (as the total width of the tags is larger):  At 1100px, the tags just about fit into their containing div.     At 800px, the tags appear on top of related questions:     At 450px, the tags are now wider than the view (the last tag is completely off the screen), causing scroll bars to appear:      This doesn't happen to lists of questions - the tags flow onto multiple lines:     Reproduced on: { Firefox 81, Chrome 84, Edge 84 } on Windows 10, and Chrome 85 on Android 11.