how to define a function that reads tuples of strings

Question

i wrote this code:

`

def key_gen(l):
   lettersi = ()
   for a in range(l[0], l[4]):
      letters1 = lettersi + (a,)
   for b in range(l[5], l[9]):
      letters2 = lettersi + (b,)
   for c in range(l[10], l[14]):
      letters3 = lettersi + (c,) 
   for d in range(l[15], l[19]):
      letters4 = lettersi + (d,)
   for e in range(l[20], l[24]):
      letters5 = lettersi + (e,)
   key = letters1 + letter2+ letter3 + letters4 + letters5
   return key

`

i run it and while im on the python shell...:

letters = ('A','B','C','D','E','F', 'G','H','I','J', ' ', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'X', 'Z', '.')

    >>>key_gen(letters)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 3, in key_gen
    TypeError: 'str' object cannot be interpreted as an integer

I dont know what mistake im making here because im a beginner in python but i want the output to be like this. Do you have any idea how to fix it?

>>>key_gen(letters)


((‘A’, ‘B’, ‘C’, ‘D’, ‘E’), (‘F’, ‘G’, ‘H’, ‘I’, ‘J’), (‘ ’, ‘L’, ‘M’, ‘N’, ‘O’), (‘P’, ‘Q’, ‘R’, ‘S’, ‘T’), (‘U’, ‘V’, ‘X’, ‘Z’, ‘.’))

maybe the function i defined cannot read tuples of strings but i dont know how to do that and ive already googled it and couldnt find anything.

Generally, lists are used more than tuples, is there a reason you are preferring tuples for this work? — Steven Rumbalski, Oct 21 '16 at 17:12
`tuple(letters[i:i+5] for i in range(0, len(letters), 5))` accomplishes what you want. — Steven Rumbalski, Oct 21 '16 at 17:15

score 3 · Accepted Answer · edited May 23 '17 at 12:06

range() expects its parameters to be of int type, and by passing l[0] you are actually passing it as char 'A'. I think what you want to do is:

for a in range(0, 4):
      letters1 = lettersi + (l[a],)

# instead of:
# for a in range(l[0], l[4]):
#       letters1 = lettersi + (a,)

There are some existing approaches to do what you are trying to achieve. Refer: How do you split a list into evenly sized chunks?. But what I would have done is not mentioned over there. My approach would have been using list slicing with list comprehension as:

>>> [letters[i:i+5] for i in range(0, len(letters), 5)]
[('A', 'B', 'C', 'D', 'E'), ('F', 'G', 'H', 'I', 'J'), (' ', 'L', 'M', 'N', 'O'), ('P', 'Q', 'R', 'S', 'T'), ('U', 'V', 'X', 'Z', '.')]

how to define a function that reads tuples of strings

1 Answers1