mean

来源： https://stackoverflow.com/questions/23395366/mean-by-factor-by-level

来源： https://stackoverflow.com/questions/23395366/mean-by-factor-by-level

来源： https://stackoverflow.com/questions/23395366/mean-by-factor-by-level

来源： https://stackoverflow.com/questions/23395366/mean-by-factor-by-level

来源： https://stackoverflow.com/questions/60462269/why-isnt-nodejs-loading-css-style-sheets-linked-to-html-files

问题 I'm very new to R (moving over from SPSS). I'm using RStudio on a Mac running Mavericks. Please answer my question in words of 2 syllables as this is my first real attempt at anything like this. I've worked through some basic tutorials and can make things work on all the sample data. I have a data set with 64,000-ish rows and about 20 columns. I want to get the mean of the variable "hold_time", but whatever I try I get either NA or NA and a warning message I have tried all of the following: >

问题 I'm very new to R (moving over from SPSS). I'm using RStudio on a Mac running Mavericks. Please answer my question in words of 2 syllables as this is my first real attempt at anything like this. I've worked through some basic tutorials and can make things work on all the sample data. I have a data set with 64,000-ish rows and about 20 columns. I want to get the mean of the variable "hold_time", but whatever I try I get either NA or NA and a warning message I have tried all of the following: >

问题 Data Please, I need to calculate the mean of the column "Sepal.Length" for the specie virginica in this data.frame: Sepal.Length Sepal.Width Petal.Length Petal.Width Species 1 5.1 3.5 1.4 0.2 setosa 2 4.9 3.0 1.4 0.2 setosa 3 4.7 3.2 1.3 0.2 setosa 4 4.6 3.1 1.5 0.2 setosa 5 5.0 3.6 1.4 0.2 setosa 6 5.4 3.9 1.7 0.4 setosa 7 4.6 3.4 1.4 0.3 setosa 8 5.0 3.4 1.5 0.2 setosa 9 4.4 2.9 1.4 0.2 setosa 10 4.9 3.1 1.5 0.1 setosa 11 5.4 3.7 1.5 0.2 setosa 12 4.8 3.4 1.6 0.2 setosa 13 4.8 3.0 1.4 0.1

问题 I have an array like this var temp = [{"rank":3,"name":"Xan"},{"rank":1,"name":"Man"},{"rank":2,"name":"Han"}] I am trying to sort it as follows temp.sort(function(a){ a.rank}) But its n ot working.Can anyone suggest help.Thanks. 回答1: With Array#sort, you need to check the second item as well, for a symetrical value and return a value. var temp = [{ rank: 3, name: "Xan" }, { rank: 1, name: "Man" }, { rank: 2, name: "Han" }]; temp.sort(function(a, b) { return a.rank - b.rank; }); console.log

问题 I have an array like this var temp = [{"rank":3,"name":"Xan"},{"rank":1,"name":"Man"},{"rank":2,"name":"Han"}] I am trying to sort it as follows temp.sort(function(a){ a.rank}) But its n ot working.Can anyone suggest help.Thanks. 回答1: With Array#sort, you need to check the second item as well, for a symetrical value and return a value. var temp = [{ rank: 3, name: "Xan" }, { rank: 1, name: "Man" }, { rank: 2, name: "Han" }]; temp.sort(function(a, b) { return a.rank - b.rank; }); console.log