“适当地”操纵“光标”使用扫描仪读取输入文件时
这是从 .txt 输入文件中的文本行中提取字符和字符串的“正确方法”吗？
Scanner scan, readLine;
System.out.print("Enter the name of your transaction file please (include .txt extension): ");
transFilename = scan.nextLine();
scan = new Scanner(new FileReader(transFilename));
while (scan.hasNext())
{
// read a whole line, then use scanner to parse
readLine = new Scanner(scan.nextLine());
code = readLine.next().toUpperCase().charAt(0);
switch (code) {
case 'A':
lineinput = readLine.next();
filename = lineinput;
System.out.println(filename);
Scanner input = new Scanner( new FileReader(filename));
break;
}
示例输入文本文件内容如下：
A blahblah.txt
B
A gahgah.txt
当这行代码运行时： lineinput = readLine.next(); 在 while 循环迭代期间，光标是否返回到行首？我只想知道扫描仪“光标”如何穿过每一行。
例子：（^代表光标位置）：
A blahblah.txt
^
Is this the "proper way" to pull a char and string from a line of text in a .txt input file?
Scanner scan, readLine;
System.out.print("Enter the name of your transaction file please (include .txt extension): ");
transFilename = scan.nextLine();
scan = new Scanner(new FileReader(transFilename));
while (scan.hasNext())
{
// read a whole line, then use scanner to parse
readLine = new Scanner(scan.nextLine());
code = readLine.next().toUpperCase().charAt(0);
switch (code) {
case 'A':
lineinput = readLine.next();
filename = lineinput;
System.out.println(filename);
Scanner input = new Scanner( new FileReader(filename));
break;
}
sample input text file reads:
A blahblah.txt
B
A gahgah.txt
When this line of code runs: lineinput = readLine.next();
Does the cursor go back to the beginning of the line during that iteration of the while loop? I just want to know how the scanner "cursor" moves through each line.
example: (^ represents the cursor position):
A blahblah.txt
^
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每次循环时，您都会从文件扫描器中获取新行，然后创建一个仅在该行上迭代的新 Scanner 实例。在
lineinput = readLine.next();之后，光标位于'A'行上的文件名之后；然而外部扫描仪的光标位于下一行的开头。On each pass through your loop, you fetch a new line from the file scanner and then create a new Scanner instance that iterates only over that line. After
lineinput = readLine.next();, the cursor is after the filename on the'A'line; however the cursor of the outer Scanner is at the beginning of the next line.