有趣的统计英文字母频率的例子
统计的是英文版”悲惨世界”，代码如下，使用ascii值做数组下标直接赋值：
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.text.DecimalFormat;
public class EnglishAlphaBetaStatics {
public static final String EN_FOLDER = "C:/resources/Books/English/Les Miserables.txt";
private static final int ASCII_START = 33; // ASCII from 33; ignore the
// space
private static final int ASCII_LENGTH = 94;
private int[] result = new int[ASCII_LENGTH];
private int total = 0;
/**
* Handle one English fiction
*
* @param file
* @throws IOException
*/
public void handleOneFile(File file) throws IOException {
if (file == null)
throw new NullPointerException();
BufferedReader in = new BufferedReader(new FileReader(file));
String line;
while ((line = in.readLine()) != null) {
for (int i = 0; i < line.length(); i++) {
char c = line.charAt(i);
if (c >= ASCII_START && c < ASCII_START + ASCII_LENGTH) {
result[c - ASCII_START] += 1;
total++;
} else {
}
}
}
in.close();
}
/**
* Print the statics result
*/
public void printResult() {
// For sorting
int[] abc = new int[ASCII_LENGTH];
for (int i = 0; i < abc.length; i++) {
abc[i] = ASCII_START + i;
}
// Sorting
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result.length - 1 - i; j++) {
if (result[j] < result[j + 1]) {
int tmp = result[j];
result[j] = result[j + 1];
result[j + 1] = tmp;
// swap the characters
tmp = abc[j];
abc[j] = abc[j + 1];
abc[j + 1] = tmp;
}
}
}
// Format
DecimalFormat df = new DecimalFormat("#.######");
System.out.println("Total characters: " + total);
System.out.println("Char\tNumber\t%");
System.out.println("-----------------------------------");
for (int i = 0; i < result.length; i++) {
char c = (char) abc[i];
double rate = result[i] * 100.0 / total;
System.out.println(c + "\t" + result[i] + "\t" + df.format(rate)
+ "%");
}
}
/**
* @param args
*/
public static void main(String[] args) throws IOException {
EnglishAlphaBetaStatics eab = new EnglishAlphaBetaStatics();
eab.handleOneFile(new File(EN_FOLDER));
eab.printResult();
}
} 我以为会多慢呢，没想到瞬间完成，统计结果如下：
Total characters: 2800496
Char Number %
e 345891 12.351062%
t 235280 8.401369%
a 211330 7.546163%
o 190799 6.813043%
h 180302 6.438217%
n 176170 6.290671%
i 174552 6.232896%
s 166855 5.958052%
r 152896 5.459604%
d 113123 4.039392%
l 102527 3.66103%
u 70975 2.534372%
c 66061 2.358904%
m 59036 2.108055%
w 56513 2.017964%
f 56476 2.016643%
, 51714 1.846601%
g 48633 1.736585%
p 41978 1.498949%
y 39999 1.428283%
b 36215 1.293164%
. 32322 1.154153%
v 25400 0.906982%
k 14724 0.525764%
" 14616 0.521908%
T 12625 0.450813%
- 10222 0.365007%
I 9530 0.340297%
A 6890 0.246028%
H 6553 0.233994%
M 6435 0.229781%
; 6204 0.221532%
E 4313 0.154008%
S 4292 0.153259%
C 4262 0.152187%
x 3882 0.138618%
' 3852 0.137547%
! 3690 0.131762%
O 3593 0.128299%
j 3495 0.124799%
B 3476 0.124121%
W 3316 0.118408%
? 3094 0.11048%
R 3057 0.109159%
P 3047 0.108802%
F 2811 0.100375%
N 2751 0.098233%
: 2553 0.091162%
J 2536 0.090555%
q 2535 0.09052%
G 2401 0.085735%
L 2296 0.081985%
V 2021 0.072166%
z 1960 0.069988%
D 1735 0.061953%
Y 1147 0.040957%
U 768 0.027424%
1 687 0.024531%
K 600 0.021425%
8 422 0.015069%
* 303 0.01082%
X 262 0.009355%
2 243 0.008677%
3 237 0.008463%
` 227 0.008106%
5 203 0.007249%
[ 197 0.007034%
] 197 0.007034%
0 195 0.006963%
4 155 0.005535%
7 142 0.005071%
6 133 0.004749%
Q 121 0.004321%
9 113 0.004035%
( 95 0.003392%
) 95 0.003392%
Z 58 0.002071%
_ 40 0.001428%
| 36 0.001285%
{ 2 0.000071%
} 2 0.000071%
+ 1 0.000036%
/ 1 0.000036%
# 0 0%
$ 0 0%
% 0 0%
& 0 0%
< 0 0%
= 0 0%
> 0 0%
@ 0 0%
\ 0 0%
^ 0 0%
~ 0 0%