Force anything to be a string.

[Tim Peters]

[jonathon]
> 	I'm reworking a script, and keep running into this
> 	same basic sequence of errors.
>
> 	The offending lines are:
>
>    string_check = check_list[50]
>    string_check = str(string_check)
>    string_check = string.capwords(string_check)
>    check_list[50] = string_check
>
> 	This code snippet is supposed to take the object
> 	at check_list[50], convert it to a string, and
> 	then capitalize each word.
> #
> 	If fed a "normal" string of characters, it works.
> 	However, if check_list[50] is an integer, I either
> 	see the following error message:
>
> 	File "mass.py", line 20402 in align_everything(record_list)
> 	string_check = string.capwords(string_check)
> 	File "/usr/local/bin/python1.5/string.py" line 542 in capwords
> 	return join(map(capitalize, split(s, sep)), sep or' ')
>     TypeError: arguement 1: expected read-only character buffer, int found
>
> 	or I see this error message:
>
> 	File "mass.py" , line 20402 in align_everything(record_list)
> 	string_check = str(string_check)
>     TypeError: call of non-function ( type string )
>
> 	The difference is whether I have removed the line
> 	"string_check = str(string_check)"
> #

Makes sense so far.

> 	Question:
>
> 	1:	How can I ensure that string_check becomes a string,
> 	and not remain an integer?  [  Other than error trapping at
> 	the source. An option not available, since this script reads
> 	files with bad data in them, to correct them. ]

Using the builtin str function was the correct approach from the start.
>From the error msgs you're getting, it looks most likely that you
accidentally rebound the name "str" to a string, so "str" no longer refers
to the builtin function (builtin function names are not reserved, which is
both a feature and a bug <0.7>).

This is how str normally works when applied to an integer:

>>> str(42)
'42'
>>>

Here's what happens if you bind "str" to a string by mistake:

>>> str = 'oops'
>>> str(42)
Traceback (innermost last):
  File "<stdin>", line 1, in ?
TypeError: call of non-function (type string)
>>>

The error msg there should look familiar.  It's telling you that the syntax
looks like a call, but the object in the caller's position *can't* be called
("call of non-function"); and it's also giving the type of the object that
can't be called (str is of "type string").

diagnosis-may-be-easier-than-cure-ly y'rs  - tim