你所要求的应该通过四舍五入的方法来解决，比如内置的 round 功能。那就让 float 数字可以自然地以其 string 代表性。

>>> round(65.53, 4)  # num decimal <= precision, do nothing
'65.53'
>>> round(40.355435, 4)  # num decimal > precision, round
'40.3554'
>>> round(0, 4)  # note: converts int to float
'0.0'

对不起，我只能做到：

' {:0.4f}'.format(1./2.).rstrip('0')

更正：

ff=1./2.
' {:0.4f}'.format(ff).rstrip('0')+'0'[0:(ff%1==0)]

>>> def pad(float, front = 0, end = 4):
    s = '%%%s.%sf' % (front, end) % float
    i = len(s)
    while i > 0 and s[i - 1] == '0':
        i-= 1
    if s[i - 1] == '.' and len(s) > i:
        i+= 1 # for 0.0
    return s[:i] + ' ' * (len(s) - i)

>>> pad(0, 3, 4)
'0.0   '
>>> pad(65.53, 3, 4)
'65.53  '
>>> pad(40.355435, 3, 4)
'40.3554'