Tagged Questions
0
votes
1answer
80 views
Matching letters in 2 strings with haskell
I just started with haskell and im wondering if there is a easy way to match the letters between 2 string and output them.
like:
iced and liked will return i,e,d
Thank you!
4
votes
2answers
173 views
Removing a string from a list of strings in Haskell
I have a question regarding Haskell that's been stumping my brain. I'm currently required to write a function that removes a string i.e. "word" from a list of strings ["hi", "today", "word", "Word", ...
4
votes
2answers
104 views
Replacing strings with strings from a list
I am trying to write a function that takes a list of searchwords, a list of replacementwords and a string on which those will be used.
listReplace :: [String] -> [String] -> String -> ...
2
votes
3answers
118 views
Haskell - filter string list based on some conditions
I am new in this comunity. I learn Haskell and have difficulties with Haskell-coding.
I hope you can help me.
I searched here and in Google, without any success.
My problem ist as fowllows:
I want ...
0
votes
2answers
132 views
How to replace more than one element at the same time in a String (Haskell)
i want to take 2 lists for example like this;
find=["Hou","House","Mouse"]
repl=["Mou","Bird","House"]
So when i give a text like that;
"The House with Mouse is big"
Output should be this;
"The ...
0
votes
3answers
95 views
List included in another list in haskell
I want to see if a list is included in another list and extract that list from a list of lists, for example i want to see if ["bc","abc"] is included in ...
0
votes
1answer
117 views
Break string into substring in haskell
I am having a problem with my function, I want to do a pattern matching on a string with my function but I have a problem with breaking the string into substrings. I want for a string like ...
1
vote
2answers
84 views
Haskell, returning String while using IO Integer to compute that string
Today I ran into the following problem:
I can read the current screen resolution in Haskell using Xlib-bindings using a function called getScreenWidth (--> I get an IO Integer). This is working so ...
0
votes
4answers
118 views
Concatenate String and IO Integer in Haskell
I wrote a function returning the current screen width as IO Integer (working so far).
getScreenWidth:: IO Integer
getScreenWidth = do
(sx, sy, w, h) <- getScreenDim 0
...
0
votes
1answer
91 views
parsing parentheses from a string
So I have a logical statement such as "((A o B) a B) o (B a C)" and I want to parse each set of statements within the parenthesis to each part in a list... here is what i have so far but since im new ...
2
votes
1answer
83 views
++ operator with String and IO String
explandDol :: String -> String -> [String] -> IO String
explandDol conclusion operators atoms =
let (ys,zs) = splitAt (head (take 1 replacement)) conclusion in ys ++ getConclusion ...
0
votes
1answer
42 views
Rvar to String when randomizing list comprehension
Hey so im trying to pick a random element from this list of list Strings however when i try to add choice to the list comprehension ...
{-# LANGUAGE UnicodeSyntax #-}
import System.Random(randomRIO)
...
1
vote
1answer
84 views
List from Int to specific Strings
What would I do if I wanted to turn a list of Ints such as [1,2,3] to ["∧","∨","→"] (so if there is a '1' turn it into the '∧' etc...)
1
vote
2answers
113 views
Haskell- IO String get multiple Lines
I am trying to write a function that gets multiple string inputs and terminates on an empty line ('\n') I have following
getLines :: IO [String]
getLines = do x <- getLine
if x == ""
...
-1
votes
2answers
132 views
Listing a deck's 52 cards in a fixed order of strings - Haskell [closed]
I am looking for a way to list all the 52 cards a deck contains as strings in a particular order:
Ace of Clubs, Two of Clubs ... Jack of Clubs followed by Ace of Diamonds ... Jack of Diamonds and so ...
7
votes
2answers
231 views
Haskell printf to String
Is there the sprintf equivalent in Haskell?
I need to convert with format Double values into String, so, Is there another way without using printf kind of functions.
The main problem is avoid:
...
8
votes
5answers
238 views
Do some replacement in Haskell List Comprehensions
My questions is if I put in a string containing such as Hello, today is a Nice Day!! How could I get rid of spaces and punctuation and also replacing the uppercase letters with lowercase?
I know how ...
2
votes
1answer
262 views
Haskell Couldn't match expected type 'String' with actual type 'Char'
I am wondering why I'm getting this error. It's for an assignment where i'm to convert from an integer to a hex value. I call this helper conversion function when I mod the integer value by 16. ...
2
votes
1answer
213 views
How can I replace a substring of a string with another in Haskell without using external Libraries like MissingH?
I would like to replace a substring with a string in haskell, without using external libraries, and, if it is possible, with good performance.
I thought about using the Data.Text replace functions, ...
1
vote
2answers
145 views
Haskell String to List of Strings using Words
I'm rather new to Haskell, and I'm currently using LearnYouAHaskell.
I am trying to take a string separated by white space, and break it into a list of smaller word strings.
My current program:
main ...
4
votes
2answers
176 views
Converting Data.Text to Int in Haskell
In another question, one of the comments says, "[Data.]Text is becoming the de-facto textual implementation. String is still around for legacy reasons and for simple things, but for serious textual ...
10
votes
3answers
185 views
Type-safe printf
The standard library provides a printf function which manages to be varadic. What it doesn't do, however, is compile-time checking of whether the argument types match the format string. That would ...
0
votes
1answer
62 views
Working with lists
I am a beginner, and write implementation of hangman in haskell.
Necessary to show guessed characters in '*'-like string, currently I use that code:
proceed char word progress = let zprog = zip ...
11
votes
3answers
281 views
Why is Haskell's default string implementation a linked list of chars?
The fact that Haskell's default String implementation is not efficient both in terms of speed and memory is well known. As far as I know the [] lists in general are implemented in Haskell as ...
0
votes
6answers
167 views
How can I count Integers in a List of String. Haskell
There is a list of String ["f", "1", "h", "6", "b", "7"].
How can I count Int in this list?
Now I have this algorithm but it's not so good.
import Data.Char
let listOfStrings = ["f", "1", "h", ...
4
votes
2answers
101 views
Typeclass in haskell
I'm extremely new to haskell and was trying to implement a small and a simple function that takes two strings and tells me the number of same characters at the same location.
ed :: (Integral b) => ...
0
votes
2answers
76 views
finding the size of a list consisting of lists
I've been trying to make a function in Haskell that has as an input a list that consists of lists and (it might sound pretty simple) I want this function to check if the input is a correct table with ...
3
votes
1answer
110 views
Strings differing by only one character
So, I'm kinda new to Haskell (and programming generally) and I've been trying to solve a problem for a while. I want to make a function, that has as an input 2 alphanumerics (type String) and that ...
1
vote
2answers
77 views
Check For Free Variables
Parse errors are currently my least favorite type of Haskell error. So I'm writing a function where I get a list of pairs where the second component contains some variables (this is determined by ...
2
votes
2answers
82 views
Two Substitutions as Arguments
I'm writing a Haskell function that takes 2 substitutions as arguments. I've handled the case where if either of the arguments is Nothing, then the function will return Nothing. If neither one is ...
2
votes
2answers
126 views
Dynamic programming with string keys in Haskell
Being rather new to pure functional programming idiom, I can't get how to implement this case of dynamic programming. I have a function f :: String -> [String] which is calculated recursively and ...
1
vote
3answers
131 views
Return list containing the first two strings in the list as a tuple
I am writing a Haskell function that takes a list of strings and returns a list containing the first two strings as a tuple as the result. So an example output would be:
listtuple ["bride", "zilla", ...
0
votes
3answers
83 views
Filter a list of strings using a pair of strings
I want to define a Haskell function that removes from a list of strings any string contained in a pair of strings and returns only a list that contains all the remaining strings. So an example would ...
6
votes
2answers
351 views
Concat two strings together
I want to define my own infix operator using Haskell that concats two strings together. However, I want to throw in an extra clause where the operator will concat over the overlapping elements in both ...
-2
votes
4answers
198 views
What does “<-” mean in a list comprehension?
In this code:
[x | temp <- str, x <- isVowel temp]
I'm wondering what the
<- operator does
<- str operator does
isVowel returns true if its argument is a vowel.
3
votes
1answer
340 views
Haskell solution for InterviewStreet String Similarity challenge
This is my best attempt to solve the String Similarity challenge for InterviewStreet.
import Control.Monad
import Data.Text as T
import qualified Data.Text.IO as TIO
sumSimilarities s = (T.length ...
5
votes
4answers
245 views
Is there a polymorphic `toString` function that doesn't add quotes?
In most OO languages that I'm familiar with, the toString method of a String is actually just the identity function. But in Haskell show adds double quotes.
So if I write a function something like ...
1
vote
4answers
526 views
Counting occurrences of a character in a string (Haskell) [duplicate]
Possible Duplicate:
How to find the frequency of characters in a string in Haskell?
Given an input String, I wish to count the occurrences of each character. I have two approaches (in ...
0
votes
3answers
138 views
Convert a List contains Tuples to formatted String
I have [(Double, Double)] returned list and I want to format it and return it like this String
"(Double, Double)"
values must convert to String mentioned above line as Double.
If there is more ...
2
votes
2answers
446 views
How do I properly define an empty string in haskell?
I'm having a problem with my program and I was able to isolate the problem. I managed to reduce it to this simpler problem. Lets say I have the function
fn:: String -> String
fn (x:xs)
| null ...
6
votes
2answers
295 views
Computing all possibilities of replacing one character by another
> magicFunction 'l' '_' "hello world"
["he_lo world", "hel_o world", "hello wor_d"]
Is there such a magic function in the standard Prelude or can it be composed easily with other functions?
And ...
2
votes
4answers
215 views
Complex pattern matching with strings
I have a list of strings that looks like this:
xs = ["xabbaua", "bbbaacv", "ggfeehhaa", "uyyttaccaa", "ibbatb"]
I would like to find only strings in the list which have and vocel followed by two ...
0
votes
3answers
571 views
Haskell find indices of String in String
I'm currently trying to find the indices of a particular string in another string.
So e.g. the result for string "ab" in "ababa baab ab bla ab" should be 11 and 18.
If currently have the problem that ...
3
votes
4answers
726 views
How can I parse the IO String in Haskell?
I' ve got a problem with Haskell. I have text file looking like this:
5.
7.
[(1,2,3),(4,5,6),(7,8,9),(10,11,12)].
I haven't any idea how can I get the first 2 numbers (2 and 7 above) and the list ...
0
votes
6answers
570 views
String parsing in Haskell
I am very new to Haskell and am currently trying to solve a problem that requires some string parsing. My input String contains a comma-delimited list of words in quotes. I want to parse this single ...
1
vote
2answers
133 views
Where is Network.Socket.ByteString.Lazy's sendTo?
Both Network.Socket.ByteString and Network.Socket.ByteString.Lazy have a send function.
Network.Socket.ByteString has a sendTo function, but Network.Socket.ByteString.Lazy doesn't.
How can I use ...
1
vote
3answers
249 views
split string into string in haskell
How can I split a string into another string without using Data.List.Split function?
To be more concrete: to turn "Abc" into "['A','b','c']"
0
votes
3answers
856 views
How to concat two (IO) Strings in Haskell?
I know this sound very simple, but I failed to combine two strings into a new one.
The IO String "a" from a gtk entry is fetched by
a <- (entryGetText text_field)
The goal is to combine ...
3
votes
2answers
228 views
Why Haskell alloc huge amounts of memory when working with strings?
I've written a program in Haskell which had to load and parse big text file in UTF8. The file represents a dictionary with key:value pairs on each line. In my program I want to have a Data.Map ...
0
votes
2answers
223 views
isInfixOf and finding a string within a string
The problem I have is that I am using isInfixOf on a string below to check whether the word I am looking for is within the string, the below works up to a certain point.
> "world" `isInfixOf` ...
