pattern-matching

I'd like to use sed or any command line tool to replace parts of lines by the output of shell commands. For example: Replace linux epochs by human-readable timestamps, by calling date Replace hexa dumps of a specific protocol packets by their decoded counterparts, by calling an in-house decoder sed seems best fitted because it allows to match patterns and reformat other things too, like moving bits of matches around, but is not mandatory. Here is a simplified example: echo "timestamp = 1234567890" | sed "s/timestamp = \(.*\)/timestamp = $(date -u --d @\1 "+%Y-%m-%d %T")/g" Of course, the $(...

I want to switch over possible values of two integers, or in another case two bools. For the sake of discussion, suppose I've done auto mypair = std::make_pair(foo, bar); How can I achieve the equivalent of switch(mypair) { case make_pair(true, false): cout << "true and false"; break; case make_pair(false, true) cout << "false and true"; break; case default: cout << "something else"; } with C++11? (C++14/17 also relevant if that helps)? C++'s switch statement doesn't have the pattern matching power of many other languages. You'll need to take a slightly different approach. Here's a possibility

I have 2 images, say bigImage and smallImage. I want to detect whether the smallImage is there anywhere in the bigImage, irrespective of its orientation or transforms(rotations). If its there, it should return true and otherwise return false. I have been going through the template matching (cvMatchTemplate) method in openCV, but haven't reach anywhere since there aren't much difference between the output for a true and a false match. Is my requirement still possible using cvMatchTemplate or are there any other methods in openCV for getting to this. This is a very general and very hard problem,

Suppose I have the sequence: x = c( 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0) Is there an elegant way in R to return the start and stop indices of each sequence of 1s? The answer should be a 2 column array with nRows = number of sequences of 1s: startIndx = [ 1, 5, 7 ] stopIndex = [ 2, 5, 9 ] Thanks. BSL Assuming your vector consists of 0 and 1 values: which(diff(c(0L, x)) == 1L) #[1] 1 5 7 which(diff(c(x, 0L)) == -1L) #[1] 2 5 9 Otherwise you'd need something like x <- x == 1L first. Elegant way is y <- which(x==1) startIndx <- y[!(y-1) %in% y] stopIndex <- y[!(y+1) %in% y] rbind(startIndx, stopIndex)

My JSON data looks like this: [{ "id": 1, "payload": { "location": "NY", "details": [{ "name": "cafe", "cuisine": "mexican" }, { "name": "foody", "cuisine": "italian" } ] } }, { "id": 2, "payload": { "location": "NY", "details": [{ "name": "mbar", "cuisine": "mexican" }, { "name": "fdy", "cuisine": "italian" } ] } }] given a text "foo" I want to return all the tuples that have this substring. But I cannot figure out how to write the query for the same. I followed this related answer but cannot figure out how to do LIKE . This is what I have working right now: SELECT r.res->>'name' AS feature

My codes looks like this: 1::2::Nil match { case 1::ts::Nil => "Starts with 1. More than one element" case 1::Nil => "Starts with 1. Only one element" } I tried to use 1::ts::Nil to match the List who starts with 1 and whose length is greater than 1. It workes well for 2-element list, however, this pattern doesn't work for 3-element list , for example: 1::2::3::Nil match { case 1::ts::Nil => "Starts with 1. More than one element" case 1::Nil => "Starts with 1. Only one element" } This won't work..Does anyone have ideas about this? You don't have to match on Nil. What you could do instead is

Suppose I have a table like this id data 1 0001 2 1000 3 2010 4 0120 5 0020 6 0002 sql fiddle demo id is primary key, data is fixed length string where characters could be 0, 1, 2. Is there a way to build an index so I could quickly find strings which are differ by n characters from given string? like for string 0001 and n = 1 I want to get row 6. Thanks. There is the levenshtein() function, provided by the additional module fuzzystrmatch . It does exactly what you are asking for: SELECT * FROM a WHERE levenshtein(data, '1110') = 1; SQL Fiddle. But it is not very fast. Slow with big tables,