You can do this using the str.format() method.

>>> width = 20
>>> print("{:>{width}} : {:>{width}}".format("Python", "Very Good", width=width))
              Python :            Very Good

Starting from Python 3.6 you can use f-string to do this:

In [579]: lang = 'Python'

In [580]: adj = 'Very Good'

In [581]: width = 20

In [582]: f'{lang:>{width}}: {adj:>{width}}'
Out[582]: '              Python:            Very Good'

Using no packages and no modules:

nums= [[  3, 4, -4,  -8, -10, -12,], [  5, 5,  3,  -3,  -4, -44,], [ 34,-4,-34, -22,  22,  22]]

t = ['|' + ''.join('%4i' % i for i in row) + ' |' for row in nums]
hdr = '+' +  (len(t[0])-2) * '-' + '+'
print '\n'.join( [hdr] + t + [hdr] )

This produces the output:

+-------------------------+
|   3   4  -4  -8 -10 -12 |
|   5   5   3  -3  -4 -44 |
|  34  -4 -34 -22  22  22 |
+-------------------------+

How it works:

• t = ['|' + ''.join('%4i' % i for i in row) + ' |' for row in nums]

  t contains everything except the top and bottom rows. At its heart, the numbers are formatted as fixed width and aligned according to specification %4i. %4i means allow four spaces, format as an integer, and align right. Many other specifications are possible. If you wanted, for example, to 5-space wide integers aligned left, use %-5i.

• hdr = '+' + (len(t[0])-2) * '-' + '+'

  Now that the interior rows are saved in t, we can assemble the header and trailer lines. These lines begin and end with a plus sign. The rest are filled with -.

• print '\n'.join( [hdr] + t + [hdr] )

  This adds the hdr string to the beginning and end of the list of rows t and then joins all the rows together with newline characters to make the final table.

More complex example

Let's format the above table but add the min, max, mean, and standard deviation for each row at the end of each row.

def mmmsd(row):
    mean=sum(row)/len(row)
    stddev = ( sum( (x-mean)**2.0 for x in row ) / float(len(row)) )**0.5
    return '%6i%6i%6.2f%6.2f' % (min(row), max(row), mean, stddev)

nums= [[  3, 4, -4,  -8, -10, -12,], [  5, 5,  3,  -3,  -4, -44,], [ 34,-4,-34, -22,  22,  22]]

stats = [mmmsd(row) for row in nums]
t = [10*' ' + '|' + ''.join('%6i' % i for i in row) + ' |' + st for row, st in zip(nums, stats)]
hdr = 10*' ' + '+' +  (len(t[0])-12 - len(stats[0])) * '-' + '+' + len(stats[0]) * ' '
print '\n'.join( [hdr] + t + [hdr] )

This produces the result:

          +-------------------------------------+
          |     3     4    -4    -8   -10   -12 |   -12     4 -5.00  6.18
          |     5     5     3    -3    -4   -44 |   -44     5 -7.00 17.23
          |    34    -4   -34   -22    22    22 |   -34    34  3.00 24.92
          +-------------------------------------+                        

You just need more cowbells (actually, more replacements: {}):

print "This is a number with {1} places {0:.{1}f}".format(3.14159, 2)

Or, in the example you gave:

C = ['{0:.{1}f}'.format(b, len(a.partition('.')[2])) for a,b in zip(A,B)]

Using itertools.chain():

>>> from itertools import chain

>>> my_string = "{} {} {} {} {}"
>>> my_tuple = ("hello", "world")  # tuple of length 2
>>> my_string.format(*chain(my_tuple*6)) # here 6 is some value equal to
'hello world hello world hello'          # maximum number of time for which
                                         # formatting is allowed

Alternatively, we may also do it using itertools.chain.from_iterator() and itertools.repeat() as:

>>> from itertools import chain, repeat

>>> my_string.format(*chain.from_iterable(repeat(my_tuple, 6)))
'hello world hello world hello'

Tuple will keep on repeating itself, until it fills all the formatting string.

Few other sample runs:

# format string of 5
>>> my_string = "{} {} {} {} {}"

### Tuple of length 1
>>> my_tuple = ("hello",)
>>> my_string.format(*chain(my_tuple*6))
'hello hello hello hello hello'

### Tuple of length 2
>>> my_tuple = ("hello", "world")
>>> my_string.format(*chain(my_tuple*6))
'hello world hello world hello'

### Tuple of length 3
>>> my_tuple = ("hello", "world", "2016")
>>> my_string.format(*chain(my_tuple*6))
'hello world 2016 hello world'