CODEWITHSUNDEEP
pythonpython-2.7csv
jpedder
jpedder

Reputation: 33

DictReader change keys to upper

I'm trying to resolve import issues in dictreader when fields aren't formatted as expected, forcing all fieldnames to uppercase (or lowercase) would resolve that.

Here's the basic code I'm using, though I can't seem to update the rows in dict.

f = open(sourceFile,'rb')
reader = csv.DictReader(f, dialect='excel')
for r in reader:
    r.update(dict((k.upper(), v) for k, v in r.iteritems()))

The desired output is the same list of dictionaries but will all keys set to uppercase.

I'm missing the 'update', I'm fine writing to a new list. Just getting a little frustrated.

Upvotes: 1

Views: 1998

Answers (3)

Mark Egge
Mark Egge

Reputation: 678

To avoid iterating through your entire file, modify the fieldnames attribute on the DictReader, as in:

f = open(sourceFile,'rb')
reader = csv.DictReader(f, dialect='excel')
reader.fieldnames = [name.upper() for name in reader.fieldnames]

Upvotes: 7

Martijn Pieters
Martijn Pieters

Reputation: 1122542

You could use a generator to return an uppercased keys dictionary for each row:

def uppercased(reader):
    for r in reader:
        yield {k.upper(): v for k, v in r.iteritems()}

then use this as:

with open(sourceFile,'rb') as f:
    reader = csv.DictReader(f, dialect='excel')
    for r in uppercased(reader):
        # use `r` like you normally would

Upvotes: 2

Lev Levitsky
Lev Levitsky

Reputation: 65791

If you want a new list:

new = [{k.upper(): v for k, v in r.iteritems()} for r in reader]

Or if you want to make one dict at a time:

for r in reader:
    r = {{k.upper(): v for k, v in r.iteritems()}
    # use r

Upvotes: 1

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