How to trim before and after a string in flutter-CodePudding

I have a 'textformfeild' that takes strings and I want to trim the white spaces at the begining and the end and strict the one in the middle to only one space.

for example if my string is like this:(....AB....CD.....) where the black dots represent the white spaces.

and I wanna make it look like this:(AB.CD)

any idea on how to do that? this is what I tried to do:

userWeight!.trim()

but this will remove all the white spaces including the one in the middle

CodePudding user response：

Trim will remove white spaces before and after the string..

CodePudding user response：

Trim will only remove the leading and trailing spaces or white space characters of a given string

Refer this for more:

https://api.flutter.dev/flutter/dart-core/String/trim.html

CodePudding user response：

Trim - If you use trim() this will remove only first and end of the white spaces example,

String str1 = "   Hello World  "; 
print(str1.trim());

The output will be only = Hello World

For your purpose you may use replaceAll

String str1 = "....AB....CD....."; 
print(str1.replaceAll("....","."));

The output will be = ".AB.CD."

If you still want to remove first and last . use substring

String str1 = "....AB....CD....."; 
print(str1.replaceAll("....",".").substring( 1, str1.length() - 1 ));

The output will be = "AB.CD"

This is what your expected output is.

CodePudding user response：

trim will remove letf and right spaces. you can use regx(RegExp) to remove inner spaces

void main(List<String> args) {
  String data = "       AB      CD   ";

  String result = data.trim().replaceAll(RegExp(r' \s '), ' ');

  print(result); //AB CD
}