comparison

问题 Related Bounty: 250 reputation points. I have a question regarding summary.lm() output. Firstly, here is reproducible code for my data set: Cond_Per_Row_stats<-structure(list(Participant = structure(c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 1L, 2L,

问题 In PHP , why is echo faster than print? They do the same thing... Why is one faster than the other? Do they do exactly the same thing? 回答1: echo and print are virtually (not technically) the same thing. The (pretty much only) difference between the two is that print will return the integer 1 , whereas echo returns nothing. Keep in mind that neither is actually a function, but rather language constructs. echo allows you to pass multiple strings when using it as if it were a function (e.g.,

问题 I am trying to use Linq2Sql to return all rows that contain values from a list of strings. The linq2sql class object has a string property that contains words separated by spaces. public class MyObject { public string MyProperty { get; set; } } Example MyProperty values are: MyObject1.MyProperty = "text1 text2 text3 text4" MyObject2.MyProperty = "text2" For example, using a string collection, I pass the below list var list = new List<>() { "text2", "text4" } This would return both items in my

问题 In one of our community sites, we allow users to upload images. These images are approved or rejected by our moderators. To limit the work needed by our administrators, we want to 'log' each picture that is rejected to some kind of database, and do a lookup in this database prior to submitting an image for approval. If a similar image already has been rejected, the uploaded image won't be submitted for approval. We can of course just log stuff like filename, size and MD5 of the picture for

问题 I'm working on something for an image processing task (it's not greatly relevant here), and I stumbled across behaviour of F#'s Option type that surprised me, regarding performing greater than (>) comparisons. I couldn't find anything that directly explained what I should expect (more on that below) on Stack Overflow, the F# docs or the wider web. The specific part I am looking at looks something like: let sort3Elems (arr: byte option []) = if arr.[0] > arr.[1] then swap &arr.[0] &arr.[1] if

问题 I've got an application that's using string.compare(string,string) to sort some values. The thing I can't figure out is why "1022" compares as less than "10-23" and "10-23" compares as less than "1024". Is there something specific to the value of "-" that causes this result? Will that overload of string.compare give the same result with different culture settings for the same type of data (numbers with dashes)? 回答1: From the documentation of string.Compare(String, String): The comparison is

问题 var i = ['5000','35000']; alert((i[0] < i[1])?'well duh!':'fuzzy math?'); alert((Number(i[0]) < Number(i[1]))?'well duh!':'fuzzy math?'); What's happening here? In the first alert, the text string "5000" evaluates as not less than "35000". I assumed Javascript used Number() when numerically comparing strings, but apparently that's not the case. Just curious how exactly Javascript handles numerically comparing the strings of numbers by default. 回答1: Javascript compares strings by character

问题 I have three directories. I would like to compare directory1 with directory2, then take those changes/new files and copy them over to directory3. Is there an easy way to do this, maybe by using linux diff and cp commands? I'm open to ideas. Thanks! Andrew 回答1: I believe this is what you want from your description. for file in dir2/*; do file_in_dir1=dir1/$(basename ${file}) if [ ! -e ${file_in_dir1} ]; then # If the file in dir2 does not exist in dir1, copy cp ${file} dir3 elif ! diff ${file}

问题 I came across the following and was unable to grasp the reason, can anyone explain please? var foo = [0]; console.log(foo == !foo); // true console.log(foo == foo); // true 回答1: The second comparison is simple to explain: foo is equal to itself. The first one, however, is a bit tricky: foo is an array, which is an object, which evaluates to true when coerced to boolean. So !foo is false . But foo on the left side of the comparison is not being converted to boolean. Both operands are actually

问题 When a class is IComparable , then we know everything to overload the < , > and == operators due to the CompareTo functionality, right? Then why aren't these overloaded automatically? Take a look at the example below: public class MyComparable : IComparable<MyComparable> { public int Value { get; } public MyComparable(int value) { Value = value; } public int CompareTo(MyComparable other) => Value.CompareTo(other.Value); } I was wondering why something like this wouldn't work by default: