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How can I pretty print a CSV file using Python, not any external tool?
For example I have this CSV file:
title1|title2|title3|title4
datalongdata|datalongdata|data|data
data|data|data|datalongdatadatalongdatadatalongdatadatalongdatadatalongdata
data|data'data|dat
I would like to transform it to visually look like a table. For example, to something like that:
+ --------------------------------------------------------------------------------------------------- +
| title1 | title2 | title3 | title4 |
+ --------------------------------------------------------------------------------------------------- +
| datalongdata | datalongdata | data | data |
| | | | |
| data | data | data | datalongdatadatalongdatadatalongdatadatalongdatadatalongdata |
| data | data'data | dat | |
+ --------------------------------------------------------------------------------------------------- +
273
Open the CSV file in Microsoft Excel or a compatible application, such as a text editor or Notepad. Move your cursor to an empty line and type an H in column A. Press the Tab key to move to the next column and enter the value that you want to import for that field. Repeat step b for all the fields in the row.
pretty.pretty_file(filename, ***options*)
Reads a CSV file and prints visually the data as table to a new file. filename, is the given CSV file. The optional ***options* keyword arguments is the union of Python's Standard Library csv module Dialects and Formatting Parameters and the following list:
Example:
import pretty_csv
pretty_csv.pretty_file("test.csv", header=False, border=False, delimiter="|")
Python 3:
This is a Python 2 implementation. For Python 3, you have to change the 2 occurrences of the line open(filename, "rb") as input: to open(filename, "r", newline="") as input: since csv.reader in Python 3 wants the file to be opened in text mode.
import csv
import os
def pretty_file(filename, **options):
"""
@summary:
Reads a CSV file and prints visually the data as table to a new file.
@param filename:
is the path to the given CSV file.
@param **options:
the union of Python's Standard Library csv module Dialects and Formatting Parameters and the following list:
@param new_delimiter:
the new column separator (default " | ")
@param border:
boolean value if you want to print the border of the table (default True)
@param border_vertical_left:
the left border of the table (default "| ")
@param border_vertical_right:
the right border of the table (default " |")
@param border_horizontal:
the top and bottom border of the table (default "-")
@param border_corner_tl:
the top-left corner of the table (default "+ ")
@param border_corner_tr:
the top-right corner of the table (default " +")
@param border_corner_bl:
the bottom-left corner of the table (default same as border_corner_tl)
@param border_corner_br:
the bottom-right corner of the table (default same as border_corner_tr)
@param header:
boolean value if the first row is a table header (default True)
@param border_header_separator:
the border between the header and the table (default same as border_horizontal)
@param border_header_left:
the left border of the table header (default same as border_corner_tl)
@param border_header_right:
the right border of the table header (default same as border_corner_tr)
@param newline:
defines how the rows of the table will be separated (default "\n")
@param new_filename:
the new file's filename (*default* "/new_" + filename)
"""
#function specific options
new_delimiter = options.pop("new_delimiter", " | ")
border = options.pop("border", True)
border_vertical_left = options.pop("border_vertical_left", "| ")
border_vertical_right = options.pop("border_vertical_right", " |")
border_horizontal = options.pop("border_horizontal", "-")
border_corner_tl = options.pop("border_corner_tl", "+ ")
border_corner_tr = options.pop("border_corner_tr", " +")
border_corner_bl = options.pop("border_corner_bl", border_corner_tl)
border_corner_br = options.pop("border_corner_br", border_corner_tr)
header = options.pop("header", True)
border_header_separator = options.pop("border_header_separator", border_horizontal)
border_header_left = options.pop("border_header_left", border_corner_tl)
border_header_right = options.pop("border_header_right", border_corner_tr)
newline = options.pop("newline", "\n")
file_path = filename.split(os.sep)
old_filename = file_path[-1]
new_filename = options.pop("new_filename", "new_" + old_filename)
column_max_width = {} #key:column number, the max width of each column
num_rows = 0 #the number of rows
with open(filename, "rb") as input: #parse the file and determine the width of each column
reader=csv.reader(input, **options)
for row in reader:
num_rows += 1
for col_number, column in enumerate(row):
width = len(column)
try:
if width > column_max_width[col_number]:
column_max_width[col_number] = width
except KeyError:
column_max_width[col_number] = width
max_columns = max(column_max_width.keys()) + 1 #the max number of columns (having rows with different number of columns is no problem)
if max_columns > 1:
total_length = sum(column_max_width.values()) + len(new_delimiter) * (max_columns - 1)
left = border_vertical_left if border is True else ""
right = border_vertical_right if border is True else ""
left_header = border_header_left if border is True else ""
right_header = border_header_right if border is True else ""
with open(filename, "rb") as input:
reader=csv.reader(input, **options)
with open(new_filename, "w") as output:
for row_number, row in enumerate(reader):
max_index = len(row) - 1
for index in range(max_columns):
if index > max_index:
row.append(' ' * column_max_width[index]) #append empty columns
else:
diff = column_max_width[index] - len(row[index])
row[index] = row[index] + ' ' * diff #append spaces to fit the max width
if row_number==0 and border is True: #draw top border
output.write(border_corner_tl + border_horizontal * total_length + border_corner_tr + newline)
output.write(left + new_delimiter.join(row) + right + newline) #print the new row
if row_number==0 and header is True: #draw header's separator
output.write(left_header + border_header_separator * total_length + right_header + newline)
if row_number==num_rows-1 and border is True: #draw bottom border
output.write(border_corner_bl + border_horizontal * total_length + border_corner_br)
answered Sep 20 '22 19:09
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