Use of the Qstring class (all-encompassing, extremely convenient)

The Qstring class of QT provides a convenient interface for string manipulation.

1. Causes a character to fill a string, meaning that all characters in the string are replaced by the equal-length ch.

Qstring::fill (Qchar ch, int size =-1)

Cases:

     QString str = "Berlin";     Str.fill (' z ');     str = = "Zzzzzz"     str.fill (' A ', 2);     str = = "AA"

2, find the same string str from the string.

int Qstring::indexof (const QString & str, int from = 0, qt::casesensitivity cs = qt::casesensitive) const

For example:

QString x = "Sticky question";     QString y = "sti";     X.indexof (y);               Returns 0     x.indexof (y, 1);            Returns     X.indexof (Y, ten);           Returns     X.indexof (Y, one);           Returns-1

3 Inserting a string at the specified location

QString & Qstring::insert (int position, const QString & str)

For example:

     QString str = "Meal";     Str.insert (1, QString ("Ontr"));     str = = "Montreal"

3 to determine if the string is empty.

BOOL Qstring::isempty () const

Such as:

     QString (). IsEmpty ();            Returns True     QString (""). IsEmpty ();          Returns True     QString ("x"). IsEmpty ();         Returns false     QString ("abc"). IsEmpty ();       Returns false

4. Determine if the string exists.

BOOL Qstring::isnull () const

For example:

     QString (). IsNull ();             Returns True     QString (""). IsNull ();           Returns false     QString ("abc"). IsNull ();        Returns false

5, the string is truncated from left to right

QString qstring::left (int n) const

For example:

     QString x = "Pineapple";     QString y = x.left (4);      y = = "Pine"

6. Intercept the string from the middle.

QString qstring::mid (int position, int n =-1) const

For example:

  QString x = "Nine pineapples";     QString y = X.mid (5, 4);            y = = "Pine"     QString z = x.mid (5);               z = = "Pineapples"

7. Remove a character from the middle of the string.

QString & Qstring::remove (int position, int n)

For example:

     QString s = "Montreal";     S.remove (1, 4);     s = = "Meal"

8, replace some characters in the string.

QString & Qstring::replace (int position, int n, const QString & After)

For example:

     QString x = "Say yes!";     QString y = "no";     X.replace (4, 3, y);     x = = "Say no!"

9, cutting a string with a character. (frequently used recently)

QString qstring::section (qchar Sep, int start, int end =-1, sectionflags flags = sectiondefault) const

For example:

   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"

10, convert integer, float, or other type to qstring

QString & Qstring::setnum (uint n, int base = 10)

Similar to the many overloaded functions, want to learn more, or to see the QT Help document.

Http://www.cnblogs.com/onlycxue/archive/2012/10/30/2746902.html

Use of the Qstring class (all-encompassing, extremely convenient)