How to make Python format floats with certain amount of significant digits?

Question

I want my Python (2.4.3) output numbers to have a certain format. Specifically, if the number is a terminating decimal with <= 6 significant digits, show it all. However,

Answer 1

try this way

a=[10188469102.605597,5.5657188485,3.539,22.1522612479,0,15.9638450858,0.284024,7.58096703786,24.3469152383]

 for i in a:
    if i >100:
        print '{:.6e}'.format(i)
    else:
        print '{:.6f}'.format(i)

for lower version of python

for i in a:
    if i >100:
        print '%6e'%i
    else:
        print '%6f'%i

output

1.018847e+10
5.565719
3.539000
22.152261
0.000000
15.963845
0.284024
7.580967
24.346915