How to write this snippet in Python?
- by morpheous
I am learning Python (I have a C/C++ background).
I need to write something practical in Python though, whilst learning. I have the following pseudocode (my first attempt at writing a Python script, since reading about Python yesterday). Hopefully, the snippet details the logic of what I want to do. BTW I am using python 2.6 on Ubuntu Karmic.
Assume the script is invoked as: script_name.py directory_path
import csv, sys, os, glob
# Can I declare that the function accepts a dictionary as first arg?
def getItemValue(item, key, defval)
return !item.haskey(key) ? defval : item[key]
dirname = sys.argv[1]
# declare some default values here
weight, is_male, default_city_id = 100, true, 1
# fetch some data from a database table into a nested dictionary, indexed by a string
curr_dict = load_dict_from_db('foo')
#iterate through all the files matching *.csv in the specified folder
for infile in glob.glob( os.path.join(dirname, '*.csv') ):
#get the file name (without the '.csv' extension)
code = infile[0:-4]
# open file, and iterate through the rows of the current file (a CSV file)
f = open(infile, 'rt')
try:
reader = csv.reader(f)
for row in reader:
#lookup the id for the code in the dictionary
id = curr_dict[code]['id']
name = row['name']
address1 = row['address1']
address2 = row['address2']
city_id = getItemValue(row, 'city_id', default_city_id)
# insert row to database table
finally:
f.close()
I have the following questions:
Is the code written in a Pythonic enough way (is there a better way of implementing it)?
Given a table with a schema like shown below, how may I write a Python function that fetches data from the table and returns is in a dictionary indexed by string (name).
How can I insert the row data into the table (actually I would like to use a transaction if possible, and commit just before the file is closed)
Table schema:
create table demo (id int, name varchar(32), weight float, city_id int);
BTW, my backend database is postgreSQL
