Creating an empty Table object in Python mode (and some other hidden "data" classes)

Processing.py
1

Another documentation gap that drives me mad is that the Python equivalent of an example like the (Java) Table t = new Table() is missing.

Table is missing from the Py.Processing.org/reference and nobody tells you how to import the needed constructor with from processing.data import Table :frowning:

So here you go:

from processing.data import Table

def setup():
  table = Table()
  
  table.addColumn("id")
  table.addColumn("species")
  table.addColumn("name")
  
  newRow = table.addRow()
  newRow.setInt("id", table.getRowCount() - 1)
  newRow.setString("species", "Panthera leo")
  newRow.setString("name", "Lion")
  
  saveTable(table, "data/new.csv")

For the curious, there are some other Python<->Java compatibility-helping objects hidden on this data module.

import processing
print(dir(processing.data))
['DoubleDict', 'DoubleList', 'FloatDict', 'FloatList', 'IntDict', 'IntList', 'JSONArray', 'JSONObject', 'JSONTokener', 'LongDict', 'LongList', 'Sort', 'StringDict', 'StringList', 'Table', 'TableRow', 'XML', '__name__']

Why not use the nice built-in Python csv module you might ask?

import csv
with open('names.csv', 'w') as csvfile:  # Python 2 has no encoding on open()
        fieldnames = ["species", "name"]
        writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
        writer.writeheader()
        writer.writerow({"species" : "Panthera Leo", "name" : u"Léo the Lion"})

I had problems with unicode strings, (non-ASCII characters) encoding it writes the file as ISO-885914 and not UTF-8 I would prefer.

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2

You can set the encoding in open()-function

with open('names.csv', 'w', encoding="utf-8") as csvfile:
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3

Hi @SomeOne!

This is Python 2.7 (Jython) and so open() has no encoding keyword argument :frowning:

A have also tried to import io and then used io.open() that is closer to Python 3 (so I tried to make it work with encoding=) but it didn’t work either for me :confused: … If anyone manages to make io.open() work with csv.DictWriter I’d be really glad. I have studied the docs, they show some enconding wrapper techiques for csv but I couldn’t manage it.

1 Like
4

I think I have the solution for the UTF-8 on Python 2 now! It is:

from codecs import open

An example:

from __future__ import unicode_literals, print_function
import csv
from codecs import open

# Define data
data = [
    (1, "maçã,", 1.0),
    (42, "manga, uva", 2.0),
    (1337, "jaca", -1),
    (0, "kiwi", 123),
    (-2, "Nada.", 3),
]
def setup():
    size(600, 600)
    background(0, 100, 0)
    # textSize(24)
    textFont(createFont('Source Code Pro', 24))

    # Write CSV file
    with open("test.csv", "wt", encoding="utf-8") as fp:
        writer = csv.writer(fp)
        # writer.writerow(["your", "header", "foo"])  # write header
        writer.writerows(data)
    
    # Read CSV file
    with open("test.csv", encoding="utf-8") as fp:
        reader = csv.reader(fp)
        # next(reader, None)  # skip the headers
        data_read = [row for row in reader]
        x, y = 20, 20
        for row in data_read:
            for item in row:
                print(item.ljust(12), end='')
                text(item.ljust(12), x, y)
                x += textWidth(item.ljust(12))
            y += 32
            x = 20
            print()

UPDATE/WARNING: csv.DictReader(file) does not work with utf-8 because of Jython limitations 13.1. csv — CSV File Reading and Writing — Jython v2.5.2 documentation csv.reader() might be unsafe too :frowning:

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