Letter frequency: Difference between revisions

This implementation will capture the frequency of all characters

<syntaxhighlight lang="java5">

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.HashMap;

import java.util.Map;

</syntaxhighlight>

<syntaxhighlight lang="java5">

public static void main(String[] args) throws IOException {

Map<Integer, Integer> frequencies = frequencies("src/LetterFrequency.java");

System.out.println(print(frequencies));

}

static String print(Map<Integer, Integer> frequencies) {

StringBuilder string = new StringBuilder();

int key;

for (Map.Entry<Integer, Integer> entry : frequencies.entrySet()) {

key = entry.getKey();

string.append("%,-8d".formatted(entry.getValue()));

/* display the hexadecimal value for non-printable characters */

if ((key >= 0 && key < 32) || key == 127) {

string.append("%02x%n".formatted(key));

} else {

string.append("%s%n".formatted((char) key));

}

}

return string.toString();

}

static Map<Integer, Integer> frequencies(String path) throws IOException {

try (InputStreamReader reader = new InputStreamReader(new FileInputStream(path))) {

/* key = character, and value = occurrences */

Map<Integer, Integer> map = new HashMap<>();

int value;

while ((value = reader.read()) != -1) {

if (map.containsKey(value)) {

map.put(value, map.get(value) + 1);

} else {

map.put(value, 1);

}

}

return map;

}

}

</syntaxhighlight>

<pre>

44 0a

463

1 !

8 "

5 %

2 &

33 (

33 )

4 *

1 +

9 ,

3 -

29 .

5 /

2 0

4 1

3 2

1 3

1 7

1 8

1 :

19 ;

7 <

12 =

7 >

2 B

4 E

4 F

2 H

18 I

2 K

2 L

8 M

3 O

3 R

13 S

1 V

1 [

1 ]

73 a

3 b

28 c

19 d

121 e

13 f

25 g

11 h

53 i

6 j

8 k

25 l

22 m

67 n

24 o

44 p

8 q

81 r

30 s

87 t

34 u

15 v

7 w

5 x

20 y

11 {

2 |

11 }

</pre>

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