How to read byte array from file in Haskell?

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When I want read bytes from a file in Java, I can do like this:

InputStream is = new FileInputStream(...);

while((int b = is.read()) != -1){

    //...analysis the bytes.

}

And how do it in Haskell? I don't see any function witch can read bytes module System.IO and Data.ByteString.

asked Jan 3 at 5:34

Jacky Wong

909

1

stackage.org/haddock/lts-12.8/bytestring-0.10.8.2/…

– Sibi
Jan 3 at 5:36

add a comment |

When I want read bytes from a file in Java, I can do like this:

InputStream is = new FileInputStream(...);

while((int b = is.read()) != -1){

    //...analysis the bytes.

}

And how do it in Haskell? I don't see any function witch can read bytes module System.IO and Data.ByteString.

asked Jan 3 at 5:34

Jacky Wong

909

1

stackage.org/haddock/lts-12.8/bytestring-0.10.8.2/…

– Sibi
Jan 3 at 5:36

add a comment |

When I want read bytes from a file in Java, I can do like this:

InputStream is = new FileInputStream(...);

while((int b = is.read()) != -1){

    //...analysis the bytes.

}

And how do it in Haskell? I don't see any function witch can read bytes module System.IO and Data.ByteString.

asked Jan 3 at 5:34

Jacky Wong

909

When I want read bytes from a file in Java, I can do like this:

InputStream is = new FileInputStream(...);

while((int b = is.read()) != -1){

    //...analysis the bytes.

}

And how do it in Haskell? I don't see any function witch can read bytes module System.IO and Data.ByteString.

haskell

asked Jan 3 at 5:34

Jacky Wong

909

asked Jan 3 at 5:34

Jacky Wong

909

asked Jan 3 at 5:34

Jacky Wong

909

asked Jan 3 at 5:34

Jacky Wong

909

asked Jan 3 at 5:34

Jacky Wong

909

1

stackage.org/haddock/lts-12.8/bytestring-0.10.8.2/…

– Sibi
Jan 3 at 5:36

add a comment |

1

stackage.org/haddock/lts-12.8/bytestring-0.10.8.2/…

– Sibi
Jan 3 at 5:36

stackage.org/haddock/lts-12.8/bytestring-0.10.8.2/…

– Sibi
Jan 3 at 5:36

add a comment |

1 Answer
1

active

oldest

votes

Use readFile

import Data.ByteString(readFile)



main = do 

    content <-  Data.ByteString.readFile "path/to/file"

    print content

It read the file and print it content on screen.

edited Jan 3 at 6:25

answered Jan 3 at 5:44

talex

11.9k11749

Yes, I know this, but it reads String from a file.

– Jacky Wong
Jan 3 at 5:47

1

It read ByteString which is in fact array of Word8 which is smart way to name byte.

– talex
Jan 3 at 5:49

So you mean I don't need to import ByteString to read Word8 which like Byte in Java ?

– Jacky Wong
Jan 3 at 5:53

Easiest way to check that is to try, but yes, you don't need to import it.

– talex
Jan 3 at 5:57

@talex the readFile in prelude reads into a String. It appears the question asker wants to read into bytes rather then characters. I think ByteString is the correct thing for that.

– Potato44
Jan 3 at 6:20

|
show 2 more comments

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1 Answer
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active

oldest

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1 Answer
1

active

oldest

votes

Use readFile

import Data.ByteString(readFile)



main = do 

    content <-  Data.ByteString.readFile "path/to/file"

    print content

It read the file and print it content on screen.

edited Jan 3 at 6:25

answered Jan 3 at 5:44

talex

11.9k11749

Yes, I know this, but it reads String from a file.

– Jacky Wong
Jan 3 at 5:47

1

It read ByteString which is in fact array of Word8 which is smart way to name byte.

– talex
Jan 3 at 5:49

So you mean I don't need to import ByteString to read Word8 which like Byte in Java ?

– Jacky Wong
Jan 3 at 5:53

Easiest way to check that is to try, but yes, you don't need to import it.

– talex
Jan 3 at 5:57

@talex the readFile in prelude reads into a String. It appears the question asker wants to read into bytes rather then characters. I think ByteString is the correct thing for that.

– Potato44
Jan 3 at 6:20

|
show 2 more comments

Use readFile

import Data.ByteString(readFile)



main = do 

    content <-  Data.ByteString.readFile "path/to/file"

    print content

It read the file and print it content on screen.

edited Jan 3 at 6:25

answered Jan 3 at 5:44

talex

11.9k11749

Yes, I know this, but it reads String from a file.

– Jacky Wong
Jan 3 at 5:47

1

It read ByteString which is in fact array of Word8 which is smart way to name byte.

– talex
Jan 3 at 5:49

So you mean I don't need to import ByteString to read Word8 which like Byte in Java ?

– Jacky Wong
Jan 3 at 5:53

Easiest way to check that is to try, but yes, you don't need to import it.

– talex
Jan 3 at 5:57

@talex the readFile in prelude reads into a String. It appears the question asker wants to read into bytes rather then characters. I think ByteString is the correct thing for that.

– Potato44
Jan 3 at 6:20

|
show 2 more comments

Use readFile

import Data.ByteString(readFile)



main = do 

    content <-  Data.ByteString.readFile "path/to/file"

    print content

It read the file and print it content on screen.

edited Jan 3 at 6:25

answered Jan 3 at 5:44

talex

11.9k11749

Use readFile

import Data.ByteString(readFile)



main = do 

    content <-  Data.ByteString.readFile "path/to/file"

    print content

It read the file and print it content on screen.

edited Jan 3 at 6:25

answered Jan 3 at 5:44

talex

11.9k11749

edited Jan 3 at 6:25

answered Jan 3 at 5:44

talex

11.9k11749

answered Jan 3 at 5:44

talex

11.9k11749

answered Jan 3 at 5:44

talex

11.9k11749

Yes, I know this, but it reads String from a file.

– Jacky Wong
Jan 3 at 5:47

1

It read ByteString which is in fact array of Word8 which is smart way to name byte.

– talex
Jan 3 at 5:49

So you mean I don't need to import ByteString to read Word8 which like Byte in Java ?

– Jacky Wong
Jan 3 at 5:53

Easiest way to check that is to try, but yes, you don't need to import it.

– talex
Jan 3 at 5:57

@talex the readFile in prelude reads into a String. It appears the question asker wants to read into bytes rather then characters. I think ByteString is the correct thing for that.

– Potato44
Jan 3 at 6:20

|
show 2 more comments

Yes, I know this, but it reads String from a file.

– Jacky Wong
Jan 3 at 5:47

1

It read ByteString which is in fact array of Word8 which is smart way to name byte.

– talex
Jan 3 at 5:49

So you mean I don't need to import ByteString to read Word8 which like Byte in Java ?

– Jacky Wong
Jan 3 at 5:53

Easiest way to check that is to try, but yes, you don't need to import it.

– talex
Jan 3 at 5:57

@talex the readFile in prelude reads into a String. It appears the question asker wants to read into bytes rather then characters. I think ByteString is the correct thing for that.

– Potato44
Jan 3 at 6:20

Yes, I know this, but it reads String from a file.

– Jacky Wong
Jan 3 at 5:47

It read ByteString which is in fact array of Word8 which is smart way to name byte.

– talex
Jan 3 at 5:49

So you mean I don't need to import ByteString to read Word8 which like Byte in Java ?

– Jacky Wong
Jan 3 at 5:53

Easiest way to check that is to try, but yes, you don't need to import it.

– talex
Jan 3 at 5:57

@talex the readFile in prelude reads into a String. It appears the question asker wants to read into bytes rather then characters. I think ByteString is the correct thing for that.

– Potato44
Jan 3 at 6:20

|
show 2 more comments

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