subset

Return data subset time frames within another timeframes?

由 冷暖自知 提交于 2019-11-26 10:09:33
问题 There are very nifty ways of subsetting xts objects. For example, one can get all the data for all years, months, days but being strictly between 9:30 AM and 4 PM by doing: my_xts[\"T09:30/T16:00\"] Or you can get all the observations between two dates by doing: my_xts[\"2012-01-01/2012-03-31\"] Or all the dates before/after a certain date by doing: my_xts[\"/2011\"] # from start of data until end of 2011 my_xts[\"2011/\"] # from 2011 until the end of the data How can I get all the data for

算法刷题分类

由 喜欢而已 提交于 2019-11-26 09:51:44
算法分类 分类及每个类型的经典题目： Pattern: Sliding window，滑动窗口类型 经典题目： Maximum Sum Subarray of Size K (easy) Smallest Subarray with a given sum (easy) Longest Substring with K Distinct Characters (medium) Fruits into Baskets (medium) No-repeat Substring (hard) Longest Substring with Same Letters after Replacement (hard) Longest Subarray with Ones after Replacement (hard) Pattern: two points, 双指针类型 经典题目： Pair with Target Sum (easy) Remove Duplicates (easy) Squaring a Sorted Array (easy) Triplet Sum to Zero (medium) Triplet Sum Close to Target (medium) Triplets with Smaller Sum (medium) Subarrays with Product

How to iteratively generate k elements subsets from a set of size n in java?

由 早过忘川 提交于 2019-11-26 09:50:31
问题 I\'m working on a puzzle that involves analyzing all size k subsets and figuring out which one is optimal. I wrote a solution that works when the number of subsets is small, but it runs out of memory for larger problems. Now I\'m trying to translate an iterative function written in python to java so that I can analyze each subset as it\'s created and get only the value that represents how optimized it is and not the entire set so that I won\'t run out of memory. Here is what I have so far and

Subset data.frame by date

由 限于喜欢 提交于 2019-11-26 09:37:15
问题 I have a dataset called EPL2011_12 . I would like to make new a dataset by subsetting the original by date. The dates are in the column named Date The dates are in DD-MM-YY format. I have tried EPL2011_12FirstHalf <- subset(EPL2011_12, Date > 13-01-12) and EPL2011_12FirstHalf <- subset(EPL2011_12, Date > \"13-01-12\") but get this error message each time. Warning message: In Ops.factor(Date, 13- 1 - 12) : > not meaningful for factors I guess that means R is treating like text instead of a

Subsetting data.table using variables with same name as column

由 为君一笑 提交于 2019-11-26 09:12:03
问题 I want to subset a data.table using a variable which has the same name as the column which leeds to some problems: dt <- data.table(a=sample(c(\'a\', \'b\', \'c\'), 20, replace=TRUE), b=sample(c(\'a\', \'b\', \'c\'), 20, replace=TRUE), c=sample(20), key=c(\'a\', \'b\')) evn <- environment() a <- \'b\' dt[a == a] #Expected Result dt[a == \'b\'] I came across this possible solution: env <- environment() dt[a == get(\'a\',env)] But it is as unhandy as: this.a = a dt[a == this.a] So is there

How to find all subsets of a set in JavaScript?

由 橙三吉。 提交于 2019-11-26 09:09:23
问题 I need to get all possible subsets of an array. Say I have this: [1, 2, 3] How do I get this? [], [1], [2], [1, 2], [2, 3], [1, 3], [1, 2, 3] I am interested in all subsets. For subsets of specific length, refer to the following questions: Finding subsets of size n: 1, 2 Finding subsets of size > 1: 1 回答1: Here is one more very elegant solution with no loops or recursion, only using the map and reduce array native functions. const getAllSubsets = theArray => theArray.reduce( (subsets, value)

Finding the subsets of an array in PHP

由 可紊 提交于 2019-11-26 08:49:44
I have a Relational Schema with attributes (A B C D). I have a set of Functional Dependencies with me too. Now I need to determine the closure for all the possible subsets of R's attributes. That's where I am stuck. I need to learn how to find subsets (non-repeating) in PHP. My Array is stored like this. $ATTRIBUTES = ('A', 'B', 'C', 'D'). so my subsets should be $SUBSET = ('A', 'B', 'C', 'D', 'AB', 'AC', AD', 'BC', 'BD', 'CD', 'ABC', 'ABD', 'BCD', 'ABCD') The code shouldn't be something big but for some reason I can't get my head around it. You wish for the power set of $attributes ? That is

R keep rows with at least one column greater than value

由 旧巷老猫 提交于 2019-11-26 08:36:47
问题 Say I have a data frame with a few hundred rows and a few hundred columns. How would I keep rows that have at least one value greater than 10? 回答1: You can use rowSums to construct the condition in base R: df[rowSums(df > 10) >= 1, ] with dplyr (0.7.0), now you can use filter_all like this: library(dplyr) filter_all(df, any_vars(. > 10)) 回答2: This is another option: df[apply(df>10,1,any),] 回答3: We can use lapply with Reduce df[Reduce(`|`, lapply(df, `>`, 10)), ] data set.seed(24) df <- as

R gotcha: logical-and operator for combining conditions is & not &&

由 非 Y 不嫁゛ 提交于 2019-11-26 08:24:39
问题 Why doesn\'t subset() work with a logical and && operator combining two conditions? > subset(tt, (customer_id==177 && visit_date==\"2010-08-26\")) <0 rows> (or 0-length row.names) but they each work individually: > subset(tt, customer_id==177) > subset(tt, visit_date==\"2010-08-26\") (Want to avoid using large temporary variables - my dataset is huge) 回答1: From the help page for Logical Operators , accessible by ?"&&" : & and && indicate logical AND and | and || indicate logical OR. The

Remove groups with less than three unique observations

由 这一生的挚爱 提交于 2019-11-26 07:49:53
问题 I would like to subset my data frame to keep only groups that have 3 or more observations on DIFFERENT days. I want to get rid of groups that have less than 3 observations, or the observations they have are not from 3 different days. Here is a sample data set: Group Day 1 1 1 3 1 5 1 5 2 2 2 2 2 4 2 4 3 1 3 2 3 3 4 1 4 5 So for the above example, group 1 and group 3 will be kept and group 2 and 4 will be removed from the data frame. I hope this makes sense, I imagine the solution will be
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