CSV Module questions.

[John D.]

I'm trying to understand how to use the "csv" module. I assume this means "comma seperated values" in files.

I quote from the docs...


http://python.org/doc/current/lib/csv-fmt-params.html
"When creating reader or writer objects, the programmer can specify a string or a subclass of the Dialect class as the dialect parameter"

Ok, that's fine and dandy, but how do I specify it when I want to create
a "writer" to write a simple dictionary to a file, and specify how it's to be written?

Example (from the docs):

# Just some stupid dictionary with key same as value.
someiterable = {'john d': 'john d', 'fred': 'fred'}

# make the writer.
writer = csv.writer(file("some.csv", "w"))
for row in someiterable:
writer.writerow(row)

Ok, so this made the file, but the file contents are thus...

$ less some.csv
j,o,h,n, ,d
f,r,e,d

which is NOT what I want. Obviously I have to probably make a "Dialect"
or something like that. But how do I do that? Obviously, since Python severely lacks acceptable example code.... why didn't they just put in a few examples of how to do this? I certainly cannot figure this out.

Here is what I want...

"john d", "john d"
"fred", "fred"

How to I write to a file in this way? Is is possible?

John

 

[Dave Cole]

I'm trying to understand how to use the "csv" module. I assume this
means "comma seperated values" in files. I quote from the docs...


http://python.org/doc/current/lib/csv-fmt-params.html "When creating
reader or writer objects, the programmer can specify a string or a
subclass of the Dialect class as the dialect parameter"

Ok, that's fine and dandy, but how do I specify it when I want to
create a "writer" to write a simple dictionary to a file, and
specify how it's to be written?

Example (from the docs):

# Just some stupid dictionary with key same as value.
someiterable = {'john d': 'john d', 'fred': 'fred'}

# make the writer.
writer = csv.writer(file("some.csv", "w"))
for row in someiterable:
writer.writerow(row)

Ok, so this made the file, but the file contents are thus...

$ less some.csv
j,o,h,n, ,d
f,r,e,d

which is NOT what I want. Obviously I have to probably make a
"Dialect" or something like that. But how do I do that? Obviously,
since Python severely lacks acceptable example code.... why didn't
they just put in a few examples of how to do this? I certainly
cannot figure this out.

Here is what I want...

"john d", "john d"
"fred", "fred"

How to I write to a file in this way? Is is possible?

When you write a "row" the writer expects the "row" to be a sequence.
Passing a string as the "row" the writer causes the string to be
handled as a row sequence thereby producing a row of single
characters.

Try this:
john d,john d
fred,fred

- Dave