Field calculate sequential letters

RIMNTIR

Hello,

I am trying to figure out how I can use the field calculator with python to calculate sequential letters. For example, I would like "A,B,C,D....Z, AA,AB, AC...".  I did find a code that works just fine in a regular python environment but I am having a hard time incorporating it on the field calculator. 

excel - How to make a continuous alphabetic list python (from a-z then from aa, ab, ac etc) - Stack Overflow 

I tried using this as the code block:

"""

from string import ascii_lowercase
  import itertools

def iter_all_strings():
   size = 1
   while True:
      for s in itertools.product(ascii_lowercase, repeat=size):
            yield "".join(s)
        size +=1

"""

and  "iter_all_strings()" as the expression in the field calculator but it just gives me null values.

Any help would be much appreciated, thank you. 

RandyBurton

And using your code, this would go in the code block:

<SPAN class="keyword token">from</SPAN> string <SPAN class="keyword token">import</SPAN> ascii_lowercase
<SPAN class="keyword token">import</SPAN> itertools

<SPAN class="keyword token">def</SPAN> <SPAN class="token function">iter_all_strings</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; size <SPAN class="operator token">=</SPAN> <SPAN class="number token">1</SPAN>
&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">while</SPAN> <SPAN class="token boolean">True</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">for</SPAN> s <SPAN class="keyword token">in</SPAN> itertools<SPAN class="punctuation token">.</SPAN>product<SPAN class="punctuation token">(</SPAN>ascii_lowercase<SPAN class="punctuation token">,</SPAN> repeat<SPAN class="operator token">=</SPAN>size<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <SPAN class="keyword token">yield</SPAN> <SPAN class="string token">""</SPAN><SPAN class="punctuation token">.</SPAN>join<SPAN class="punctuation token">(</SPAN>s<SPAN class="punctuation token">)</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; size <SPAN class="operator token">+=</SPAN><SPAN class="number token">1</SPAN>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
s <SPAN class="operator token">=</SPAN> iter_all_strings<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN>
‍‍‍‍‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

The expression would be:

s<SPAN class="punctuation token">.</SPAN>next<SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN>‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN></SPAN>

The generator needs to be set up in the code block.