dennisearlev...@gmail.com wrote:
>
> Hi,
>
> Sorry about the simple question but I am very new to Python.
>
> Anyway, I have a function that will be used to call a stored procedure
> and I need to format the string with the correct number of parameter
> markers for the ODBC driver, fairly standard stuff.
>
> What I have works but looks ugly, is there a better way to build or
> concatenate a string or is a list or a tuple a better option?
>
> the function looks like this
>
> def callSp(self, schema, spName) :
> sqlCode = "{call " + schema + "." + spName + "("
> par_Markers = ""
> y = len(self.param)
> x = 0
> while x < y :
> par_Markers = par_Markers.join("?")
> if (x < y - 1) :
> par_Markers = par_Markers.join(", ")
> x += 1
> self.cmdText = sqlCode + par_Markers + ")}"
> self.ExecuteCursor()
>
> return
>
> self.param is a list of parameters. sself.cmdText is the text that will
> be used to call the stored procedure.
>
> the function would be called like this
>
> class.AddParameter(some value 1)
> class.AddParameter(some value 2)
> callSp("schemaName", "storedProcedureName")
>
> the self.cmdText will look like this just before the ExecuteCursor call
>
> "{call schemaName.StoredProcedureName(?, ?)}"
>
> the code works, but as I said is a bit ugly, is there better methods?
If I understand you correctly you have two problems.
(1) build a string from a few parts. You can use string formatting for that:
>>> "It's a {size} {animal}".format(size="big", animal="bird")
"It's a big bird"
You can escape { and } by repeating them:
>>> "{{It's a {size} {animal}}}".format(size="big", animal="bird")
"{It's a big bird}"
(2) Build a string containing a comma-separated list with a varying number
of question marks. That's easy with str.join():
>>> ", ".join(7*"?")
'?, ?, ?, ?, ?, ?, ?'
The complete method may become
def callSp(self, schema, spName) :
qm = ", ".join("?"*len(self.param))
self.cmdText = "{{call {schema}.{procname} ({qm})}}".format(
schema=schema, procname=spName, qm=qm)
self.ExecuteCursor()
... but please consider adopting the conventions recommended in the style
guide
http://legacy.python.org/dev/peps/pep-0008/
before you write a significant amount of Python code.
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