Python: no if in second loop

Question

Im not sure if Im nuts or something, but look at this code:

a=1
while a<=2.2:
    if a==1.4:
        print "OK"
    a=a+0.4

output: "OK"

changed condition to 1.8:

a=1
while a<=2.2:
    if a==1.8:
        print "OK"
    a=a+0.4

output: nothing!?

Can anyone help me here?

I'm not sure, but my first guess is that you are having a problem with the precision of floating point numbers. Try the same with integers. — Cargo23, Jan 13 '15 at 18:59
use an epsilon, `if abs(1.8 - a) <= epsilon` where epsilon is 0.00001 — Padraic Cunningham, Jan 13 '15 at 19:13

score 1 · Answer 1 · answered Jan 13 '15 at 18:59

1

Testing random floats for equality is usually a bad idea. It's probably something like 1.799999999.

Check out this link for more information.

answered Jan 13 '15 at 18:59

Ethan Furman

score 0 · Answer 2 · answered Jan 13 '15 at 19:03

0

Try using the round function

In [19]: round(6.79999999,1)
Out[19]: 6.8

answered Jan 13 '15 at 19:03

kilojoules

2 Answers2