'%03.1f' works (1 could be any number, or empty string):

>>> "%06.2f"%3.3
'003.30'

>>> "%04.f"%3.2
'0003'

Note that the field width includes the decimal and fractional digits.

You can use the format specifiers, like this

>>> "{:0>8.4f}".format(2.02)
'002.0200'
>>> print("{:0>8.4f}".format(2.02))
002.0200
>>> 

Here, 8 represents the total width, .4 represents the precision. And 0> means that the string has to be right aligned and filled with 0 from the left.

To format a floating point number with a given precision you should use the 'f' specifier. Without it the value is formatted as a string.

>>> '{:.4f}'.format(4.1)
'4.1000

You can also specify the minimum width of the complete output and the fill character:

>>> '{:07.4f}'.format(4.1)
'04.1000'

Here the output is padded on the left with zeros to be at least 7 characters.

numbers = [23.23, 0.1233, 1.0, 4.223, 9887.2]                                                                                                                                                   
                                                                                                                                                                                                
for x in numbers:                                                                                                                                                                               
    print("{:10.4f}".format(x)) 

prints

   23.2300
    0.1233
    1.0000
    4.2230
 9887.2000

The format specifier inside the curly braces follows the Python format string syntax. Specifically, in this case, it consists of the following parts:

• The empty string before the colon means "take the next provided argument to format()" – in this case the x as the only argument.
• The 10.4f part after the colon is the format specification.
• The f denotes fixed-point notation.
• The 10 is the total width of the field being printed, lefted-padded by spaces.
• The 4 is the number of digits after the decimal point.

To pad strings:

>>> print('4'.zfill(3))
004
>>> print('-4'.zfill(3))
-04

To pad numbers:

>>> n = 4
>>> print(f'{n:03}') # Preferred method, python >= 3.6
004
>>> print('%03d' % n)
004
>>> print(format(n, '03')) # python >= 2.6
004
>>> print('{0:03d}'.format(n))  # python >= 2.6 + python 3
004
>>> print('{foo:03d}'.format(foo=n))  # python >= 2.6 + python 3
004
>>> print('{:03d}'.format(n))  # python >= 2.7 + python3
004

String formatting documentation.

What about this?

>>> '{0: <8}|'.format(str(myfloat))
'0.002   |'

Edit: following Gall's comment, this suffices

>>> '{0: <8}|'.format(myfloat)
'0.002   |'

You need a f after 3:

In [19]: "{:.3f}".format(0.12)
Out[19]: '0.120'

In case of floats if you don't specify any type then it uses 'g' by default.

In [27]: "{:.20}".format(0.12)
Out[27]: '0.11999999999999999556'

In [28]: "{:.20g}".format(0.12)
Out[28]: '0.11999999999999999556'

Documentation here.

  print "{:06.0f}".format(round(100*x))

Format floating point number with padding zeros:

Copynumbers = [0.0, 0.1, 0.29, 1.278, 59.0, 99.9]
for x in numbers:
    print("{:05.2f}".format(x).replace(".","_"))

Which prints:

Copy00_00
00_10
00_29
01_28
59_00
99_90

The :05 means 'pad with zeros using five places' and .2f means 'force show 2 digits after the decimal point'. For background on formatting numbers see: https://pyformat.info/#number.

Hat-tip: How to format a floating number to fixed width in Python