【Qt】QString 格式化參數

一、參數格式：

以下參數在QString 下的 arg(), number() 都可以使用:

 

Format	Meaning
e	format as [-]9.9e[+|-]999
E	format as [-]9.9E[+|-]999
f	format as [-]9.9
g	use e or f format, whichever is the most concise
G	use E or f format, whichever is the most concise

A precision is also specified with the argument format. For the 'e', 'E', and 'f' formats, the precision represents the number of digits after the decimal point. For the 'g' and 'G' formats, the precision represents the maximum number of significant digits (trailing zeroes are omitted).

二、示例：

示例1：

  QString i;           // current file's number
  QString total;       // number of files to process
  QString fileName;    // current file's name

  QString status = QString("Processing file %1 of %2: %3")
                  .arg(i).arg(total).arg(fileName);

First, arg(i) replaces %1. Then arg(total) replaces %2. Finally, arg(fileName) replaces %3.

示例2：

  qDebug() << "  L:" << value.Rectangle.x << " T:" << value.Rectangle.y
           << "  W:" << value.Rectangle.width << "  H:" << value.Rectangle.height
           << " Area:" << value.Area
           <<  "  Cen(" << QString::number(value.Centroid.x, 'f', 4)
           << "," << QString::number(value.Centroid.y, 'f', 4) << ")";

 

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