Index of word in string 'covering' certain position












0















Not sure if this is the right place to ask but I couldn't find any related or similar questions.



Anyway: imagine you have a certain string like



val exampleString = "Hello StackOverflow this is my question, cool right?"



If given a position in this string, for example 23, return the word that 'occupies' this position in the string. If we look at the example string, we can see that the 23rd character is the letter 's' (the last character of 'this'), so we should return index = 5 (because 'this' is the 5th word). In my question spaces are counted as words. If, for example, we were given position 5, we land on the first space and thus we should return index = 1.



I'm implementing this in Scala (but this should be quite language-agnostic and I would love to see implementations in other languages).



Currently I have the following approach (assume exampleString is the given string and charPosition the given position):



exampleString.split("((?<= )|(?= ))").scanLeft(0)((a, b) => a + b.length()).drop(1).zipWithIndex.takeWhile(_._1 <= charPosition).last._2 + 1


This works, but it is way too complex to be honest. Is there a better (more efficient?) way to achieve this. I'm fairly new to functions like fold, scan, map, filter ... but I would love to learn more.



Thanks in advance.










share|improve this question



























    0















    Not sure if this is the right place to ask but I couldn't find any related or similar questions.



    Anyway: imagine you have a certain string like



    val exampleString = "Hello StackOverflow this is my question, cool right?"



    If given a position in this string, for example 23, return the word that 'occupies' this position in the string. If we look at the example string, we can see that the 23rd character is the letter 's' (the last character of 'this'), so we should return index = 5 (because 'this' is the 5th word). In my question spaces are counted as words. If, for example, we were given position 5, we land on the first space and thus we should return index = 1.



    I'm implementing this in Scala (but this should be quite language-agnostic and I would love to see implementations in other languages).



    Currently I have the following approach (assume exampleString is the given string and charPosition the given position):



    exampleString.split("((?<= )|(?= ))").scanLeft(0)((a, b) => a + b.length()).drop(1).zipWithIndex.takeWhile(_._1 <= charPosition).last._2 + 1


    This works, but it is way too complex to be honest. Is there a better (more efficient?) way to achieve this. I'm fairly new to functions like fold, scan, map, filter ... but I would love to learn more.



    Thanks in advance.










    share|improve this question

























      0












      0








      0








      Not sure if this is the right place to ask but I couldn't find any related or similar questions.



      Anyway: imagine you have a certain string like



      val exampleString = "Hello StackOverflow this is my question, cool right?"



      If given a position in this string, for example 23, return the word that 'occupies' this position in the string. If we look at the example string, we can see that the 23rd character is the letter 's' (the last character of 'this'), so we should return index = 5 (because 'this' is the 5th word). In my question spaces are counted as words. If, for example, we were given position 5, we land on the first space and thus we should return index = 1.



      I'm implementing this in Scala (but this should be quite language-agnostic and I would love to see implementations in other languages).



      Currently I have the following approach (assume exampleString is the given string and charPosition the given position):



      exampleString.split("((?<= )|(?= ))").scanLeft(0)((a, b) => a + b.length()).drop(1).zipWithIndex.takeWhile(_._1 <= charPosition).last._2 + 1


      This works, but it is way too complex to be honest. Is there a better (more efficient?) way to achieve this. I'm fairly new to functions like fold, scan, map, filter ... but I would love to learn more.



      Thanks in advance.










      share|improve this question














      Not sure if this is the right place to ask but I couldn't find any related or similar questions.



      Anyway: imagine you have a certain string like



      val exampleString = "Hello StackOverflow this is my question, cool right?"



      If given a position in this string, for example 23, return the word that 'occupies' this position in the string. If we look at the example string, we can see that the 23rd character is the letter 's' (the last character of 'this'), so we should return index = 5 (because 'this' is the 5th word). In my question spaces are counted as words. If, for example, we were given position 5, we land on the first space and thus we should return index = 1.



      I'm implementing this in Scala (but this should be quite language-agnostic and I would love to see implementations in other languages).



      Currently I have the following approach (assume exampleString is the given string and charPosition the given position):



      exampleString.split("((?<= )|(?= ))").scanLeft(0)((a, b) => a + b.length()).drop(1).zipWithIndex.takeWhile(_._1 <= charPosition).last._2 + 1


      This works, but it is way too complex to be honest. Is there a better (more efficient?) way to achieve this. I'm fairly new to functions like fold, scan, map, filter ... but I would love to learn more.



      Thanks in advance.







      scala






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 27 '18 at 14:31









      Robin HaveneersRobin Haveneers

      426




      426
























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          def wordIndex(exampleString: String, index: Int): Int = {
          exampleString.take(index + 1).foldLeft((0, exampleString.head.isWhitespace)) {
          case ((n, isWhitespace), c) =>
          if (isWhitespace == c.isWhitespace) (n, isWhitespace)
          else (n + 1, !isWhitespace)
          }._1
          }


          This will fold over the string, keeping track of whether the previous character was a whitespace or not, and if it detects a change, it will flip the boolean and add 1 to the count (n).



          This will be able to handle groups of spaces (e.g. in hello world, world would be at position 2), and also spaces at the start of the string would count as index 0 and the first word would be index 1.



          Note that this can't handle when the input is an empty string, I'll let you decide what you want to do in that case.






          share|improve this answer























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            1 Answer
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            active

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            1 Answer
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            active

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            active

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            def wordIndex(exampleString: String, index: Int): Int = {
            exampleString.take(index + 1).foldLeft((0, exampleString.head.isWhitespace)) {
            case ((n, isWhitespace), c) =>
            if (isWhitespace == c.isWhitespace) (n, isWhitespace)
            else (n + 1, !isWhitespace)
            }._1
            }


            This will fold over the string, keeping track of whether the previous character was a whitespace or not, and if it detects a change, it will flip the boolean and add 1 to the count (n).



            This will be able to handle groups of spaces (e.g. in hello world, world would be at position 2), and also spaces at the start of the string would count as index 0 and the first word would be index 1.



            Note that this can't handle when the input is an empty string, I'll let you decide what you want to do in that case.






            share|improve this answer




























              2














              def wordIndex(exampleString: String, index: Int): Int = {
              exampleString.take(index + 1).foldLeft((0, exampleString.head.isWhitespace)) {
              case ((n, isWhitespace), c) =>
              if (isWhitespace == c.isWhitespace) (n, isWhitespace)
              else (n + 1, !isWhitespace)
              }._1
              }


              This will fold over the string, keeping track of whether the previous character was a whitespace or not, and if it detects a change, it will flip the boolean and add 1 to the count (n).



              This will be able to handle groups of spaces (e.g. in hello world, world would be at position 2), and also spaces at the start of the string would count as index 0 and the first word would be index 1.



              Note that this can't handle when the input is an empty string, I'll let you decide what you want to do in that case.






              share|improve this answer


























                2












                2








                2







                def wordIndex(exampleString: String, index: Int): Int = {
                exampleString.take(index + 1).foldLeft((0, exampleString.head.isWhitespace)) {
                case ((n, isWhitespace), c) =>
                if (isWhitespace == c.isWhitespace) (n, isWhitespace)
                else (n + 1, !isWhitespace)
                }._1
                }


                This will fold over the string, keeping track of whether the previous character was a whitespace or not, and if it detects a change, it will flip the boolean and add 1 to the count (n).



                This will be able to handle groups of spaces (e.g. in hello world, world would be at position 2), and also spaces at the start of the string would count as index 0 and the first word would be index 1.



                Note that this can't handle when the input is an empty string, I'll let you decide what you want to do in that case.






                share|improve this answer













                def wordIndex(exampleString: String, index: Int): Int = {
                exampleString.take(index + 1).foldLeft((0, exampleString.head.isWhitespace)) {
                case ((n, isWhitespace), c) =>
                if (isWhitespace == c.isWhitespace) (n, isWhitespace)
                else (n + 1, !isWhitespace)
                }._1
                }


                This will fold over the string, keeping track of whether the previous character was a whitespace or not, and if it detects a change, it will flip the boolean and add 1 to the count (n).



                This will be able to handle groups of spaces (e.g. in hello world, world would be at position 2), and also spaces at the start of the string would count as index 0 and the first word would be index 1.



                Note that this can't handle when the input is an empty string, I'll let you decide what you want to do in that case.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 27 '18 at 15:03









                TomTom

                1,73921024




                1,73921024
































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