如何计算csv文件中一行中的字符数 [英] How to count the number of characters in a line in a csv file
问题描述
我有一个Justice_League.csv文件，它们之间有四行逗号。我想计算每行中的字符数，并将该数字转换为十六进制。
下面是Justice_League.csv的内容：
Bruce Wayne，蝙蝠侠，无，Gotham City，Robin，小丑43 2B
Oliver皇后，绿箭，无，星城， ，Deathstroke 50 32
Clark Kent，超人，飞行，大都市，无，Lex Luthor 46 2E
Bart Allen，闪电，速度，中央城市，儿童Flash，教授缩放52 34
正如你所看到的，我手工计算了字符，并在其旁边写了十六进制值。现在我需要这样做在Java。这是我到目前为止。可以有人帮助我吗？
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（）;
建议您阅读 String.split 。我认为你误解了这个概念：
String [] f = line.split（，）; p>
a [count] = Integer.parseInt（f [2]）; // - > java.lang.NumberFormatException here！
避免在代码中使用'magic'数字，例如 int [] a = new int [24]; 。为什么24？
好吧，这里有一个版本，做你想做的。也许这不是最好的方法，但它的工作原理。
public void convertCSVToFlat（）throws Exception {
String csv =Justice_League.csv;
BufferedReader bReader = new BufferedReader（new FileReader（csv））;
//我们将值存储在这个数组列表中，
//但更好的方法是使用对象来保存'b
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）;
//我假设你不想计算逗号和空格。
//如果你想，注释下一行
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（）;
//只是为了显示结果
for（int i = 0; i< lines.size（）; i ++）{
System.out.print get（i））;
System.out.print（\t+ chars.get（i））;
System.out.println（\t+ hex.get（i））;
}
}
像我前面说的，这是一种解决方法这个。你应该尝试另一个选项来解决这个问题，以提高你的知识...
I have a Justice_League.csv file that has four lines with commas between them. I want to count the number of characters there are in each line and convert that number to hex.
Below is the contents of Justice_League.csv:
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. Now I need this done in Java. This is what I have so far. Can anybody help me out?
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. I think that you misunderstood the concept when you did this:
String[] f=line.split(",");
a[count]=Integer.parseInt(f[2]); //--> java.lang.NumberFormatException here!
Avoid using 'magic' numbers in your code like int[] a = new int[24];. Why 24?
Well, here comes a version that do what you want to do. Maybe it isn't the best way to do this but it works.
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. You should try another options to solve this in order to improve your knowledge...
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