Question: How can I format a hex string ('003de70fc98a') to a MAC string ('00:3d:e7:0f:c9:8a') using a concise statement?

Answer: 
```
In [104]: hexstr = '003de70fc98a'

In [105]: ':'.join([hexstr[i:i+2] for i in range(0, len(hexstr), 2)])
Out[105]: '00:3d:e7:0f:c9:8a'

```

or,

```
In [108]: ':'.join(map(''.join, zip(*[iter(hexstr)]*2)))
Out[108]: '00:3d:e7:0f:c9:8a'

```
Try this:

```
s = '003de70fc98a'
':'.join(s[i]+s[i+1] for i in range(0, len(s), 2))
=> '00:3d:e7:0f:c9:8a'

```