How can I format a number into a string with leading zeros?
Rather simple:
Key = i.ToString("D2");
D
stands for "decimal number", 2
for the number of digits to print.
Best way to format integer as string with leading zeros?
You can use the zfill()
method to pad a string with zeros:
In [3]: str(1).zfill(2)
Out[3]: '01'
Display number with leading zeros
In Python 2 (and Python 3) you can do:
number = 1
print("%02d" % (number,))
Basically % is like printf
or sprintf
(see docs).
For Python 3.+, the same behavior can also be achieved with format
:
number = 1
print("{:02d}".format(number))
For Python 3.6+ the same behavior can be achieved with f-strings:
number = 1
print(f"{number:02d}")
How to output numbers with leading zeros in JavaScript?
NOTE: Potentially outdated. ECMAScript 2017 includes
String.prototype.padStart
.
You'll have to convert the number to a string since numbers don't make sense with leading zeros. Something like this:
function pad(num, size) {
num = num.toString();
while (num.length < size) num = "0" + num;
return num;
}
Or, if you know you'd never be using more than X number of zeros, this might be better. This assumes you'd never want more than 10 digits.
function pad(num, size) {
var s = "000000000" + num;
return s.substr(s.length-size);
}
If you care about negative numbers you'll have to strip the -
and read it.
How to deal with leading zeros when formatting an int value
You can use the 0 as format specifier. From the documentation :
Replaces the zero with the corresponding digit if one is present; otherwise, zero appears in the result string.
You can do like :
02112321.ToString("00 000 000", CultureInfo.InvariantCulture)
Edit:
As indicate by @olivier-jacot-descombes, I miss a point. The OP want format a integer from a string to a string. Example "02112321"
to "02 112 321"
.
It's possible with a intermediate conversion, string to int to string. With the example, this done "02112321"
to 02112321
to "02 112 321"
:
var original = "02112321";
var toInt = int.Parse(original, CultureInfo.InvariantCulture);
var formated = toInt.ToString("00 000 000", CultureInfo.InvariantCulture)
How to format a Java string with leading zero?
In case you have to do it without the help of a library:
("00000000" + "Apple").substring("Apple".length())
(Works, as long as your String isn't longer than 8 chars.)
How to convert integer to string, preserving leading zeroes in C++ ? (Using to_string)
Integers doesn't have leading zeroes.
If you want a specific number of digits for the number, with leading zeros, you need to use I/O manipulators like set::setw
and std::setfill
:
std::cout << std::setw(8) << std::setfill('0') << n << '\n';
That will print (at least) eight digits, with leading zeros if the value of n
is not eight digits.
If you want to store a "number" with leading zeros in your program, for example a phone number or similar, then you need another data-type than plain integers (which as mentioned doesn't have leading zeros).
Most common is as a string (std::string
).
Convert int (number) to string with leading zeros? (4 digits)
Use String.PadLeft like this:
var result = input.ToString().PadLeft(length, '0');
Add leading zeroes to number in Java?
String.format (https://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html#syntax)
In your case it will be:
String formatted = String.format("%03d", num);
- 0 - to pad with zeros
- 3 - to set width to 3
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