QT 小知识之字符串处理

1 分割字符串

1）section方式

1.1)单个字符分割

QString QString::section(QChar sep, int start, int end = -1, SectionFlags flags = SectionDefault) const

  QString str;
  QString csv = "forename,middlename,surname,phone";
  QString path = "/usr/local/bin/myapp"; // First field is empty
  QString::SectionFlag flag = QString::SectionSkipEmpty;

  str = csv.section(',', 2, 2);   // str == "surname"
  str = path.section('/', 3, 4);  // str == "bin/myapp"
  str = path.section('/', 3, 3, flag); // str == "myapp"

If start or end is negative, we count fields from the right of the string, the right-most field being -1, the one from right-most field being -2, and so on.

  str = csv.section(',', -3, -2);  // str == "middlename,surname"
  str = path.section('/', -1); // str == "myapp"

1.2）字符串分割

QString QString::section(const QString &sep, int start, int end = -1, SectionFlags flags = SectionDefault) const

  QString str;
  QString data = "forename**middlename**surname**phone";

  str = data.section("**", 2, 2); // str == "surname"
  str = data.section("**", -3, -2); // str == "middlename**surname"

1.3)正则分割

QString QString::section(const QRegExp &reg, int start, int end = -1, SectionFlags flags = SectionDefault) const

This function overloads section().

This string is treated as a sequence of fields separated by the regular expression, reg.


  QString line = "forename\tmiddlename  surname \t \t phone";
  QRegExp sep("\\s+");
  str = line.section(sep, 2, 2); // str == "surname"
  str = line.section(sep, -3, -2); // str == "middlename  surname"

2）split方式

2.1）

QStringList QString::split(const QString &sep, SplitBehavior behavior = KeepEmptyParts, Qt::CaseSensitivity cs = Qt::CaseSensitive) const

  QString str = "a,,b,c";

  QStringList list1 = str.split(',');
  // list1: [ "a", "", "b", "c" ]

  QStringList list2 = str.split(',', QString::SkipEmptyParts);
  // list2: [ "a", "b", "c" ]

2.2）正则

QStringList QString::split(const QRegExp &rx, SplitBehavior behavior = KeepEmptyParts) const

Here's an example where we extract the words in a sentence using one or more whitespace characters as the separator:

  QString str;
  QStringList list;

  str = "Some  text\n\twith  strange whitespace.";
  list = str.split(QRegExp("\\s+"));
  // list: [ "Some", "text", "with", "strange", "whitespace." ]

Here's a similar example, but this time we use any sequence of non-word characters as the separator:


  str = "This time, a normal English sentence.";
  list = str.split(QRegExp("\\W+"), QString::SkipEmptyParts);
  // list: [ "This", "time", "a", "normal", "English", "sentence" ]

Here's a third example where we use a zero-length assertion, \b (word boundary), to split the string into an alternating sequence of non-word and word tokens

  str = "Now: this sentence fragment.";
  list = str.split(QRegExp("\\b"));
  // list: [ "", "Now", ": ", "this", " ", "sentence", " ", "fragment", "." ]

翻译自QT手册

来源：CSDN

作者：清水迎朝阳

链接：https://blog.csdn.net/shuilan0066/article/details/104777813

标签

qstring