[英]How to count the number of characters in a line in a csv file
I have a Justice_League.csv file that has four lines with commas between them.我有一个Justice_League.csv 文件,其中有四行,中间用逗号。 I want to count the number of characters there are in each line and convert that number to hex.
我想计算每行中的字符数并将该数字转换为十六进制。
Below is the contents of Justice_League.csv:以下是Justice_League.csv的内容:
Bruce Wayne,Batman,None,Gotham City,Robin,The Joker 43 2B
Oliver Queen,Green Arrow,None,Star City,Speedy,Deathstroke 50 32
Clark Kent,Superman,Flight,Metropolis,None,Lex Luthor 46 2E
Bart Allen,The Flash,Speed,Central City,Kid Flash,Professor Zoom 52 34
As you can see I have handcounted the characters and wrote the HEX value next to it.正如您所看到的,我已经手动计算了字符并在其旁边写了 HEX 值。 Now I need this done in Java.
现在我需要用 Java 完成。 This is what I have so far.
这是我到目前为止。 Can anybody help me out?
有人可以帮我吗?
public String convertCSVToFlat (Exchange exchange) throws Exception {
String csv="Justice_League.csv";
BufferedReader bReader = new BufferedReader(new FileReader(csv));
String line = "";
int count = 0;
String str[] = new String[200];
int[] a = new int[24];
String[] hexNumber = new String[4];
try {
bReader.readLine();
int characterSum = 0;
int i = 0;
while((line = bReader.readLine()) != null) {
String[] f=line.split(",");
a[count]=Integer.parseInt(f[2]);
str[count]=f[1];
count++;
characterSum += line.length();
hexNumber[i] = Integer.toHexString(characterSum);
i++;
}
} catch (IOException e) {
e.printStackTrace();
}
bReader.close();
return hexNumber.toString();
I suggest you to read the javadoc of String.split .我建议你阅读String.split的 javadoc 。 I think that you misunderstood the concept when you did this:
我认为你在这样做时误解了这个概念:
String[] f=line.split(",");
String[] f=line.split(",");
a[count]=Integer.parseInt(f[2]);
a[count]=Integer.parseInt(f[2]); //--> java.lang.NumberFormatException here!
//--> java.lang.NumberFormatException 在这里!
Avoid using 'magic' numbers in your code like int[] a = new int[24];
避免在代码中使用“魔法”数字,例如
int[] a = new int[24];
. . Why 24?
为什么是 24?
Well, here comes a version that do what you want to do.好吧,这里有一个可以做你想做的事情的版本。 Maybe it isn't the best way to do this but it works.
也许这不是最好的方法,但它有效。
public void convertCSVToFlat () throws Exception {
String csv="Justice_League.csv";
BufferedReader bReader = new BufferedReader(new FileReader(csv));
//We're storing the values at this 3 arraylists,
//but a better approach is using an object to hold'em
ArrayList<String> lines = new ArrayList<String>();
ArrayList<Integer> chars = new ArrayList<Integer>();
ArrayList<String> hex = new ArrayList<String>();
String line = "";
try {
while((line = bReader.readLine()) != null) {
lines.add(line);
//I'm assuming that you don't want to count the commas and spaces.
//If you want to, comment the next line
line = line.replaceAll(",", "").replaceAll(" ", "");
int c = line.length(); //count remaining chars...
chars.add(c);
hex.add(Integer.toHexString(c));
}
} catch (IOException e) {
e.printStackTrace();
}
bReader.close();
//Just to show the results
for (int i = 0; i < lines.size(); i++) {
System.out.print(lines.get(i));
System.out.print("\t" + chars.get(i));
System.out.println("\t" + hex.get(i));
}
}
Like I said previously, this is a way to solve this.就像我之前说的,这是解决这个问题的一种方法。 You should try another options to solve this in order to improve your knowledge...
您应该尝试其他选项来解决此问题以提高您的知识...
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