How to convert QString to int

Question

I have a QString in my sources   So I need to convert it to integer without  Kb     I tried Abcd toInt   but it does not work   QString Abcd    123 5 Kb

User · Answer

Don t forget to check if the conversion was successful   bool ok  auto str  tr  1337    str toDouble  amp ok      returns 1337 0  ok set to true auto strr  tr  LEET    strr toDouble  amp ok      returns 0 0  ok set to false

User · Answer

You can use   QString str    10   int n   str toInt      Output   n   10

User · Answer

You don t have all digit characters in your string  So you have to split by space  QString Abcd    123 5 Kb   Abcd split      0  toInt         convert the first part to Int Abcd split      0  toDouble      convert the first part to double Abcd split      0  toFloat       convert the first part to float   Update  I am updating an old answer  That was a straight forward answer to the specific question  with a strict assumption  However as noted by  DomTomCat in comments and  Mikhail in answer  In general one should always check whether the operation is successful or not  So using a boolean flag is necessary   bool flag  double v   Abcd split      0  toDouble  amp flag    if flag        use v     Also if you are taking that string as user input  then you should also be doubtful about whether the string is really splitable with space  If there is a possibility that the assumption may break then a regex verifier is more preferable  A regex like the following will extract the floating point value and the prefix character of  b   Then you can safely convert the captured strings to double     0-9      0-9    s   w bB     You can have an utility function like the following  QPair lt double  QString gt  split size str const QString amp  str       QRegExp regex    0-9       0-9     s    w bB          int pos   regex indexIn str       QStringList captures   regex capturedTexts        if captures count    gt  1           double value   captures 1  toDouble       should succeed as regex matched         QString unit   captures 2      should succeed as regex matched         return qMakePair value  unit             return qMakePair 0 0f  QString

User · Answer

On the comments   sscanf Abcd    f  s    amp f  amp s     Gives  an Error   This is the right way   sscanf Abcd    f  s    amp f qPrintable s

User · Answer

The string you have here contains a floating point number with a unit  I d recommend splitting that string into a number and unit part with QString  split     Then use toDouble   to get a floating point number and round as you want

User · Answer

Use  toInt   for int  toFloat   for float and  toDouble   for double  toInt

User · Answer

As a suggestion  you also can use the QChar  digitValue   to obtain the numeric value of the digit  For example   for  int var   0  var  lt  myString length      var        bool ok      if  myString at var  isDigit             int digit   myString at var  digitValue              DO SOMETHING HERE WITH THE DIGIT           Source  Converting one element from a QString to int

[c++] How to convert QString to int?

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