How to remove trailing zeros using Dart - dart

Question

I would like the optimal solution for removing trailing zeros using Dart. If I have a double that is 12.0 it should output 12. If I have a double that is 12.5 it should output 12.5

Answer 1

I made regular expression pattern for that feature.
double num = 12.50; // 12.5
double num2 = 12.0; // 12
double num3 = 1000; // 1000
RegExp regex = RegExp(r'([.]*0)(?!.*\d)');
String s = num.toString().replaceAll(regex, '');

Answer 2

UPDATE
A better approach, just use this method:
String removeDecimalZeroFormat(double n) {
return n.toStringAsFixed(n.truncateToDouble() == n ? 0 : 1);
}
OLD
This meets the requirements:
double x = 12.0;
double y = 12.5;
print(x.toString().replaceAll(RegExp(r'.0'), ''));
print(y.toString().replaceAll(RegExp(r'.0'), ''));
X Output: 12
Y Output: 12.5

Answer 3

Use NumberFormat:
String formatQuantity(double v) {
if (v == null) return '';
NumberFormat formatter = NumberFormat();
formatter.minimumFractionDigits = 0;
formatter.maximumFractionDigits = 2;
return formatter.format(v);
}

Answer 4

If what you want is to convert a double without decimals to an int but keep it as a double if it has decimals, I use this method:
num doubleWithoutDecimalToInt(double val) {
return val % 1 == 0 ? val.toInt() : val;
}

Answer 5

Lots of the answers don't work for numbers with many decimal points and are centered around monetary values.
To remove all trailing zeros regardless of length:
removeTrailingZeros(String n) {
return n.replaceAll(RegExp(r"([.]*0+)(?!.*\d)"), "");
}
Input: 12.00100003000
Output: 12.00100003
If you only want to remove trailing 0's that come after a decimal point, use this instead:
removeTrailingZerosAndNumberfy(String n) {
if(n.contains('.')){
return double.parse(
n.replaceAll(RegExp(r"([.]*0+)(?!.*\d)"), "") //remove all trailing 0's and extra decimals at end if any
);
}
else{
return double.parse(
n
);
}
}

Answer 6

I found another solution, to use num instead of double. In my case I'm parsing String to num:
void main() {
print(num.parse('50.05').toString()); //prints 50.05
print(num.parse('50.0').toString()); //prints 50
}

Answer 7

Here is what I've come up with:
extension DoubleExtensions on double {
String toStringWithoutTrailingZeros() {
if (this == null) return null;
return truncateToDouble() == this ? toInt().toString() : toString();
}
}
void main() {
group('DoubleExtensions', () {
test("toStringWithoutTrailingZeros's result matches the expected value for a given double",
() async {
// Arrange
final _initialAndExpectedValueMap = <double, String>{
0: '0',
35: '35',
-45: '-45',
100.0: '100',
0.19: '0.19',
18.8: '18.8',
0.20: '0.2',
123.32432400: '123.324324',
-23.400: '-23.4',
null: null
};
_initialAndExpectedValueMap.forEach((key, value) {
final initialValue = key;
final expectedValue = value;
// Act
final actualValue = initialValue.toStringWithoutTrailingZeros();
// Assert
expect(actualValue, expectedValue);
});
});
});
}

Answer 8

String removeTrailingZero(String string) {
if (!string.contains('.')) {
return string;
}
string = string.replaceAll(RegExp(r'0*$'), '');
if (string.endsWith('.')) {
string = string.substring(0, string.length - 1);
}
return string;
}
======= testcase below =======
000 -> 000
1230 -> 1230
123.00 -> 123
123.001 -> 123.001
123.00100 -> 123.001
abc000 -> abc000
abc000.0000 -> abc000
abc000.001 -> abc000.001

Answer 9

Here is a very simple way. Using if else I will check if the number equals its integer or it is a fraction and take action accordingly
num x = 24/2; // returns 12.0
num y = 25/2; // returns 12.5
if (x == x.truncate()) {
// it is true in this case so i will do something like
x = x.toInt();
}

Answer 10

To improve on What #John's answer: here is a shorter version.
String formatNumber(double n) {
return n.toStringAsFixed(0) //removes all trailing numbers after the decimal.
}

Answer 11

This function removes all trailing commas. It also makes it possible to specify a maximum number of digits after the comma.
extension ToString on double {
String toStringWithMaxPrecision({int? maxDigits}) {
if (round() == this) {
return round().toString();
} else {
if (maxDigits== null) {
return toString().replaceAll(RegExp(r'([.]*0)(?!.*\d)'), "");
} else {
return toStringAsFixed(maxDigits)
.replaceAll(RegExp(r'([.]*0)(?!.*\d)'), "");
}
}
}
}
//output without maxDigits:
// 1.0 -> 1
// 1.0000 -> 1
// 0.99990 -> 0.9999
// 0.103 -> 0.103
//
////output with maxDigits of 2:
// 1.0 -> 1
// 1.0000 -> 1
// 0.99990 -> 0.99
// 0.103 -> 0.1

Answer 12

user3044484's version with Dart extension:
extension StringRegEx on String {
String removeTrailingZero() {
if (!this.contains('.')) {
return this;
}
String trimmed = this.replaceAll(RegExp(r'0*$'), '');
if (!trimmed.endsWith('.')) {
return trimmed;
}
return trimmed.substring(0, this.length - 1);
}
}

Answer 13

// The syntax is same as toStringAsFixed but this one removes trailing zeros
// 1st toStringAsFixed() is executed to limit the digits to your liking
// 2nd toString() is executed to remove trailing zeros
extension Ex on double {
String toStringAsFixedNoZero(int n) =>
double.parse(this.toStringAsFixed(n)).toString();
}
// It works in all scenarios. Usage
void main() {
double length1 = 25.001;
double length2 = 25.5487000;
double length3 = 25.10000;
double length4 = 25.0000;
double length5 = 0.9;
print('\nlength1= ' + length1.toStringAsFixedNoZero(3));
print('\nlength2= ' + length2.toStringAsFixedNoZero(3));
print('\nlenght3= ' + length3.toStringAsFixedNoZero(3));
print('\nlenght4= ' + length4.toStringAsFixedNoZero(3));
print('\nlenght5= ' + length5.toStringAsFixedNoZero(0));
}
// output:
// length1= 25.001
// length2= 25.549
// lenght3= 25.1
// lenght4= 25
// lenght5= 1

Answer 14

you can do a simple extension on the double class
and add a function which in my case i called it neglectFractionZero()
in this extension function on double(which returns a string) i
split the converted number to string and i check if the split part of the string is "0" , if so i return the first part only of the split and i neglect this zero
you can modify it according to your needs
extension DoubleExtension on double {
String neglectFractionZero() {
return toString().split(".").last == "0"? toString().split(".").first:toString();
}
}

Answer 15

I've came up with improved version of #John.
static String getDisplayPrice(double price) {
price = price.abs();
final str = price.toStringAsFixed(price.truncateToDouble() == price ? 0 : 2);
if (str == '0') return '0';
if (str.endsWith('.0')) return str.substring(0, str.length - 2);
if (str.endsWith('0')) return str.substring(0, str.length -1);
return str;
}
// 10 -> 10
// 10.0 -> 10
// 10.50 -> 10.5
// 10.05 -> 10.05
// 10.000000000005 -> 10

Answer 16

void main() {
double x1 = 12.0;
double x2 = 12.5;
String s1 = x1.toString().trim();
String s2 = x2.toString().trim();
print('s1 is $s1 and s2 is $s2');
}
try trim method https://api.dartlang.org/stable/2.2.0/dart-core/String/trim.html