gistfile1.txt

In [5]: for i in range(10) + ['missing'] + range(11,50):
   ...:         print float(i)
   ...:
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-5-d62628a1bc7e> in <module>()
      1 for i in range(10) + ['missing'] + range(11,50):
----> 2         print float(i)
      3

ValueError: could not convert string to float: missing


In [8]: %paste
for i in range(10) + ['missing'] + range(11,50):
    try:
        print float(i)
    except:
        import code
        code.interact(local=locals())

## -- End pasted text --
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
Python 2.7.8 (default, Oct  2 2014, 13:50:25)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.51)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> print float(i)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
ValueError: could not convert string to float: missing
>>> print repr(i)
'missing'
>>> ^D
11.0
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
31.0
32.0
33.0
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
45.0
46.0
47.0
48.0
49.0