How do I parse a string into a number with Dart

Question

I would like to parse strings like  1  or  32 23  into integers and doubles  How can I do this with Dart

User · Answer

In Dart 2 int tryParse is available   It returns null for invalid inputs instead of throwing  You can use it like this   int val   int tryParse text     defaultValue

User · Answer

You can parse a string into an integer with int parse    For example   var myInt   int parse  12345    assert myInt is int   print myInt      12345   Note that int parse   accepts 0x prefixed strings  Otherwise the input is treated as base-10   You can parse a string into a double with double parse    For example   var myDouble   double parse  123 45    assert myDouble is double   print myDouble      123 45   parse   will throw FormatException if it cannot parse the input

User · Answer

As per dart 2 6    The optional onError parameter of int parse is deprecated  Therefore  you should use int tryParse instead   Note  The same applies to double parse  Therefore  use double tryParse instead                            The  onError  parameter is deprecated and will be removed       Instead of  int parse string  onError   string    gt              you should use  int tryParse string                                   external static int parse String source   int radix   deprecated int onError String source       The difference is that int tryParse returns null if the source string is invalid              Parse  source  as a  possibly signed  integer literal and return its value            Like  parse  except that this function returns  null  where a      similar call to  parse  would throw a  FormatException        and the  source  must still not be  null           external static int tryParse String source   int radix      So  in your case it should look like      Valid source value int parsedValue1   int tryParse  12345    print parsedValue1      12345     Error handling int parsedValue2   int tryParse      if  parsedValue2    null      print parsedValue2      null           handle the error here

User · Answer

Convert String to Int var myInt   int parse  12345    assert myInt is int   print myInt      12345 print myInt runtimeType    Convert String to Double var myDouble   double parse  123 45    assert myInt is double   print myDouble      123 45 print myDouble runtimeType    Example in DartPad

User · Answer

void main      var x    quot 4 quot     int number   int parse x    STRING to INT    var y    quot 4 6 quot     double doubleNum   double parse y    STRING to DOUBLE    var z   55    String myStr   z toString     INT to STRING     int parse   and double parse   can throw an error when it couldn t parse the String

User · Answer

you can parse string with int parse  your string value     Example - int num   int parse  110011    print num      prints 110011

[dart] How do I parse a string into a number with Dart?

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