Python CSV Demo

By Dr. Louay Chebib

https://github.com/Netuser-Py/pythoncsvdemo

Python CSV Demo

• What is CSV
• Python CSV
• Demo

Python CSV Demo

What is CSV?

• CSV = Comma Separated Values file
• Plain Text file with record delimiters (\r\n)
• Usually Comma or Tab delimited fields with or without quotes (") for text fields
• Generally used with Spreadsheets Such as MS Excel
• Database Structure is First Normal Form

Python CSV Demo

Python CSV

• Python Native CSV support with Import csv

• csv.list_dialects() -> ['excel', 'excel-tab', 'unix']

• The reader is hard-coded to recognise either '\r' or '\n' as end-of-line,  and ignores lineterminator.

• lineterminator="\n" (unix); lineterminator="\r\n" is ignored

• for tab, use: delimiter='\t' in the open

• csv.Sniffer is used to deduce the format of a CSV file

• Related Excel functions in openpyxl

https://docs.python.org/3/library/csv.html

https://districtdatalabs.silvrback.com/simple-csv-data-wrangling-with-python

https://github.com/jdunck/python-unicodecsv

https://pypi.python.org/pypi/unicodecsv/0.9.0

https://automatetheboringstuff.com/chapter12/

Python CSV Demo

Demo

• Start with an Excel file (CLNTCodesDomo1.xlsx) and save as comma delimited CSV
• Note the multi-line cell

• load_CLNT():

  • pre-process: replace single b'\n' -> b'|' 

  • uses tempfile.TemporaryFile()
• write_test(): write tempfile to disk
• input_CSVfile(): load to Hold_recs
• Make_sheet(): write to a workbook