How to Add Leading Zeros to Numbers in Flutter/Dart

In this example, we will show you how to add or attach a leading zero at the left of the number, or pad trailing zero at the right of the number in Flutter or Dart. This function is necessary when you are making any length of the number to the same width of strings with leading zeros. 

How to Add Leading Zeros to Number at Left:

String number = "345";
String number2 = "345345";

String numbera = number.padLeft(10, "0");
print(numbera); //Output: 0000000345

String numberb = number2.padLeft(10, "0");
print(numberb); //Output: 0000345345

Here, the number and number2 Strings have different lengths, but with padLeft(), you can make the same length of string with leading zeros. You can also replace zeros with any other characters to add at the leading of any string, for Example:

String number2 = "345345";

String numberc = number2.padLeft(10, "R");
print(numberc); //Output: RRRR345345

Here, we have attached other characters instead of zero.

How to Attache Character on the Right side of the String:

String number2 = "345345";

String numberd = number2.padRight(10, "D");
print(numberd); //output: 345345DDDD

Here, we have attached "D' at the right side of the string to fulfill its length to 10. 

In this way, you can add leading or trailing zeros on numbers in Dart or Flutter.