pattern-matching

问题 What is the purpose of & in the code &i in list ? If I remove the & , it produces an error in largest = i , since they have mismatched types (where i is &32 and i is i32 ). But how does &i convert i into i32 ? fn largest(list: &[i32]) -> i32 { println!("{:?}", list); let mut largest = list[0]; for &i in list { if i > largest { largest = i; } } largest } fn main() { let hey = vec![1, 3, 2, 6, 90, 67, 788, 12, 34, 54, 32]; println!("The largest number is: {}", largest(&hey)); } Playground It

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed last month . I'm back with my survey data. This time, I need to remove a specific set of rows from data when they occur. In our survey, an automated telephone survey, the survey tool will attempt three times during that call to prompt the respondent to enter a response. After three timeouts of

问题 I am fairly new to Scala, and would like to know if it is possible for a match to execute multiple matching cases at once. Without getting into too much detail, I am basically working on a function that "scores" a certain piece of text according to various traits; these traits can overlap, and multiple traits can be true for one given string. To illustrate what I want in code, it would look something like this: Say we have a String, str , with a value of "Hello World". I would like something

问题 I am fairly new to Scala, and would like to know if it is possible for a match to execute multiple matching cases at once. Without getting into too much detail, I am basically working on a function that "scores" a certain piece of text according to various traits; these traits can overlap, and multiple traits can be true for one given string. To illustrate what I want in code, it would look something like this: Say we have a String, str , with a value of "Hello World". I would like something

问题 Anybody have a nice tight and efficient SQL Server function that will return the fist string (terminated by a whitespace) following the first match of a given string. I've got some code, but it's real ugly and probably slow. For example, in In test 12545 file:x12545.jpg appears to be good given file: would return x12345.jpg Thanks. 回答1: create function dbo.extractAfter(@full nvarchar(max), @part nvarchar(max)) returns nvarchar(max) with returns null on null input as begin return ltrim(stuff

问题 How would you go about splitting a normal string in to as many identical pieces as possible whilst using all characters. For example a = "abab" Would return "ab" , whereas with b= "ababc" It would return "ababc" , as it can't be split into identical pieces using all letters. 回答1: This is very similar, but not identical, to How can I tell if a string repeats itself in Python? – the difference being that that question only asks to determine whether a string is made up of identical repeating

问题 I am new to this forum. I guess something like this has been asked before but, I am not really sure if that is what I want. I have a sequence like this, 1 2 3 4 5 8 9 10 12 14 15 17 18 19 So, what I wish to do is this, get all the numbers which form a series,i.e.the numbers that belonging to that set should all have a constant difference with the previous element, and also the minimum number of elements should be 3 in that set. i.e., I can see that (1,2,3,4,5) forms one such series in which

问题 I am new to this forum. I guess something like this has been asked before but, I am not really sure if that is what I want. I have a sequence like this, 1 2 3 4 5 8 9 10 12 14 15 17 18 19 So, what I wish to do is this, get all the numbers which form a series,i.e.the numbers that belonging to that set should all have a constant difference with the previous element, and also the minimum number of elements should be 3 in that set. i.e., I can see that (1,2,3,4,5) forms one such series in which

问题 I'm actually working on a website where there are two tables, almost identical, where MATCH AGAINST works on one but not on the other. To find out why I've tried to reduce this to a simple, "Let's make a simple table work" - but it doesn't. I'm doing testing with phpMyAdmin and this is MySQL 5.1.41. The test I build used the following to define the table... CREATE TABLE IF NOT EXISTS `test` ( `id` int(11) NOT NULL, `title` text NOT NULL, `body` text NOT NULL, PRIMARY KEY (`id`) ) ENGINE

问题 My requirement is to get multiple regex patterns in a given String. "<a href=\"https://page1.google.com/ab-cd/ABCDEF\”>Hello</a> hiiii <a href=\"https://page2.yahoo.com/gr\”>page</a><img src=\"https://image01.google.com/gr/content/attachment/987654321\” alt=\”demo image\”></a><a href=\"https://page3.google.com/hr\">" With this below code: val p = Pattern.compile("href=\"(.*?)\"") val m = p.matcher(str) while(m.find()){ println(m.group(1)) } I am getting output: https://page1.google.com/ab-cd