I have a TextField and controller. I am trying to find word inside this controller.
This is the text from TextField:
Hello people, from Mars
I tried this and this code returning how many word the controller has. So, it is 4.
int mLength = controller1.text.split(' ').length;
debugPrint(mLength.toString());
Then I tried the find last word with this code:
debugPrint(controller1.text.split(" ").elementAt(isimLenght - 1));
But the problem has begin here. How do I know, how many word written by user? Maybe 4, maybe 10..
If I try to get first word or third word or seventh word, how do I get it?
I tried to use for and for in but couldn't handle with these.
CodePudding user response：
So the issue is that you don't know the number of words in advance, but you still need to get some words at precise positions. You can do it this way:
var words = controller1.text.split(' ');
var fourthWord = ''; //assign here a default value, so you have the variable available later
var tenthWord = '';
//and so on, for each word in a precise position you need
if (words.length> 3){
fourthWord = words[3];
}
if (words.length> 9){
tenthWord = words[9];
}
//and so on...
//I suppose you need these words for something: in this way you have all of them set by default as empty
processWords(fourthWord, tenthWord);
Another way is by using try...catch to get the errors, but the result is pretty much the same. Short example, instead of using if:
try{
fourthWord=words[3];
} catch (e) {
print('Not enough words');
}
}
CodePudding user response：
controller1.text is of String type which means all the methods from String class can be used to search a word, replace, find lenght etc.
controller1.text.split(' ') returns an array of Strings which means all the operations allowed on arrays or Lists are also by default possible here.
Search a specific word:
controller1.text.contains('from'); // Returns TRUE/FALSE
controller1.text.indexOf('from'); // Returns the start index
Get the count of words:
List<String> words = controller1.text.split(' ');
debugPrint(words[5]);
CodePudding user response：
You can get an array of words by:
var words = controller1.text.split(' ');
Iterating them:
for (var word in words) {
print(word);
}
Pick one of them:
var picked = words[2];
How many words did the user input?
var count = words.length;
print('words: $count');
If you want to split the string by a space and the input contains no space at all, the result array will contain only 1 element - the whole string. But we could define a word without using a space separator. Maybe just an arbitrary string, try this example:
void test() {
var fullText = 'foobarfoofoobarbar';
var searchFrom = 0;
var keyword = 'foo';
var index = fullText.indexOf(keyword, searchFrom);
//will quit the loop if 'foo' cannot be found anymore
while (index != -1) {
//first word 'foo' starts from index to index 3
var firstFoo = fullText.substring(index, index keyword.length);
print('word $firstFoo: $index ${index keyword.length}');
//find next word 'foo' from index after the last one:
searchFrom = index;
index = fullText.indexOf('foo', searchFrom);
}
}
Didn't test it yet so no guaranteed it's working. But you could get the idea of searching inside a string.
CodePudding user response：
var h = "Hello people, from Mars Hello==1 people1==, from1== Mars1==";
var split = h.split(" ");
printme(split, 0);
printme(split, 1);
printme(split, 2);
printme(split, 3);
printme(split, 4);
printme(split, 5);
printme(split, 6);
printme(split, 7);
printme(split, 8);
printme(split, 9);
printme(split, 10);
printme(split, 11);
printme(split, 12);
printme(split, 100);
printme(split, -1);
}
printme(split, int t) {
var st = split.length - t.abs() > 0 ? split.elementAt(t.abs()) : "";
print("$t=============>" st);
return st;
}
Output
0=============>Hello
1=============>people,
2=============>from
3=============>Mars
4=============>Hello==1
5=============>people1==,
6=============>from1==
7=============>Mars1==
8=============>
9=============>
10=============>
11=============>
12=============>
100=============>
-1=============>people,
Smaple Codedart pad code
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
TextEditingController _textcontroller= new TextEditingController(
text: "Hello people, from Mars Hello==1 people1==, from1== Mars1==");
TextEditingController _textlengthcontroller = new TextEditingController();
var text = "";
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter ;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: <Widget>[
TextFormField(
controller: _textcontroller,
),
Container(
height: 100,
child: TextFormField(
controller: _textlengthcontroller,
keyboardType: TextInputType.number,
),
),
Text(
text,
),
ElevatedButton(
onPressed: () {
var s = printme(_textcontroller.text.split(" "),
int.parse(_textlengthcontroller.text));
setState(() {
text = s;
});
},
child: Text("Find My word"))
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
printme(split, int t) {
var st = split.length - t.abs() > 0
? split.elementAt(t.abs())
: " ===============No WordFound=========";
print("$t=============>" st);
return st;
}
}