mean

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Is it the time when I click the send button on my HTML form, or the time when it arrives to the server? <?php echo $_SERVER['REQUEST_TIME']; ?> Edit: I have already read the manual, Googled other sources - including SO. The clearest definition I've found is still ambigous to me, as I don't know what the start of the request means exactly in the definition below. 'REQUEST_TIME' The timestamp of the start of the request . Available since PHP 5.1.0. http://php.net/manual/en/reserved.variables.server.php It could mean the moment when the request

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: What does the notation somevar >> 0 mean in javascript? Thanks 回答1: In a >> b , >> is a bitwise operator that shifts a in binary representation b (https://developer.mozilla.org/en/JavaScript/Reference/Operators/Bitwise_Operators 回答2: Bitwise right shift . Although somevar >> 0 looks weird. 回答3: It's a bitwise operator. In this case, for shifting the first operand in binary representation the number of bits to the right specified in the second operand, discarding bits shifted off. With a 0 as second operand, I guess it has no effect (shifting

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I am trying to run a module from the console. The structure of my directory is this: I am trying to run the module p_03_using_bisection_search.py , from the problem_set_02 directory using: $ python3 p_03_using_bisection_search . py The code inside p_03_using_bisection_search.py is: __author__ = 'm' """ Docstring """ from . p_02_paying_debt_off_in_a_year import compute_balance_after def compute_bounds ( balance : float , annual_interest_rate : float ) -> ( float , float ): """" Docstring """ # there is code here, but I have omitted

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I have one column which contains the group ID of each participant. There are three groups so every number in this column is 1, 2 or 3. Then I have a second column which contains response scores for each participant. I want to calculate the mean/median response score within each group. I have managed to do this by looping through every row but I sense this is a slow and suboptimal solution. Could someone please suggest a better way of doing things? 回答1: Use logic conditions, for example say your data is in matrix m as follows: the

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm very confused about how to use git archive . I have a git repository with folder Foo , Bar and Baz at the top level. I need to export folder Foo in a SVN-ish sort of way for quick test deployment. I learned that I could use git-archive in an SVN-ish export sort of way . But here's the thing, The following works fine: git archive master | tar -x -C ~/destination it results in Foo , Bar , Baz folders in the destination folder. However, the following will error out with fatal not a valid object name : git archive master/foo | tar -x -C ~

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: This is my code html, body { width: 100%; height: 100%; padding: 0; margin: 0; } body { font-family: 'Open Sans'; } .navigation { padding: 0; margin: 0; background: #333; position: fixed; top: 0; z-index: 999; width: 100% li { display: inline; padding: 5px 10px; a { color: #e1e1e1; text-decoration: none; a:hover{color: lighten(#e1e1e1, 20%);} } } } But whenever I build it and refresh the webpage I get this error: Syntax error: Illegal nesting: Only properties may be nested beneath properties. on line 23 of style.scss here is the my css code

虽然我也粗读过统计学的几本书，但从易懂性来说，都没有学校老师给的ppt好，或者说自己看书比较困难，但是听老师讲课就很容易懂。所以，我建议有条件的同学能够选修统计学这门课，没条件的同学可以去网上找一些相关视频，配套书籍可以选择茆诗松的《概率论与数理统计》。另外，《Head First Statistics》一书可以用来预热。 学了统计学，你至少应该知道： 基本的抽样方法 数据分布的描述统计量有哪些？一组样本数据分布的数值特诊可以从三个方面进行描述： 描述水平的统计量： 数据的水平：也称为集中趋势或位置度量，反应全部数据的数值大小。 均值、中位数、分位数、众数 描述差异的统计量 数据的差异：反应数据间的离散程度。 极差和四分位差、方差和标准差、变异系数、标准分数 描述分布形状的统计量 分布的形状：反应数据分布的偏度和峰度。 偏度系数、峰度系数 你需要了解一些重要的分布，比如正态分布、chi-square分布、t分布、F分布等。 假设检验是用来做什么的、置信区间的概念、MSE （Mean Squared Error）均方误差、RMSE（Root Mean Squard Error）均方根误差、MAE(平均绝对误差)、R-squared（拟合优度）的含义等等。 怎样进行数据预处理 怎样整理和显示数据 你需要了解各种图的作用和适用场景，常用图包括条形图、饼图、直方图、折线图、箱线图、散点图

I have a data frame df with rows that are duplicates for the names column but not for the values column: name value etc1 etc2 A 9 1 X A 10 1 X A 11 1 X B 2 1 Y C 40 1 Y C 50 1 Y I need to aggregate the duplicate names into one row, while calculating the mean over the values column. The expected output is as follows: name value etc1 etc2 A 10 1 X B 2 1 Y C 45 1 Y I have tried to use df[duplicated(df$name),] but of course this does not give me the mean over the duplicates. I would like to use aggregate() , but the problem is that the FUN part of this function will apply to all the other columns

I'm trying to get the mean length of fasta sequences using Erlang . A fasta file looks like this >title1 ATGACTAGCTAGCAGCGATCGACCGTCGTACGC ATCGATCGCATCGATGCTACGATCGATCATATA ATGACTAGCTAGCAGCGATCGACCGTCGTACGC ATCGATCGCATCGATGCTACGATCTCGTACGC >title2 ATCGATCGCATCGATGCTACGATCTCGTACGC ATGACTAGCTAGCAGCGATCGACCGTCGTACGC ATCGATCGCATCGATGCTACGATCGATCATATA ATGACTAGCTAGCAGCGATCGACCGTCGTACGC >title3 ATCGATCGCATCGAT(...) I tried to answser this question using the following Erlang code: -module(golf). -export([test/0]). line([],{Sequences,Total}) -> {Sequences,Total}; line(">" ++ Rest,{Sequences,Total}) ->

#!/usr/bin/env python3 def mean_x(): s = 0.0 n = 0 while True: s += yield n+=1 print("s =", s, "n=", n) print("mean = ", s/n) x = mean_x() next(x) while True: print("please input number...") x.send(float(input())) 能写出类似的例子，就是理解协程了。 来源： CSDN 作者： 未济2019 链接： https://blog.csdn.net/u011539200/article/details/81039846