;examples: csv: add an example python converter script

examples/csv/csv-hledger-1.py

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+#!/usr/bin/env python3
+# An example of using Python to convert a certain CSV to hledger journal entries.
+# This won't work as-is (unless you have this particular kind of CSV);
+# use it for inspiration. hledger's own CSV rules are not used at all here.
+
+
+__version__ = "1.0"
+__author__ = "Simon Michael"
+
+VERSION = "%prog " + __version__
+USAGE = """%prog [options] [CSVFILE [JOURNALFILE]]
+Reads a [certain kind of] CSV, writes a hledger journal.
+Journal entries will be in the same order as the CSV records.
+
+Requirements: python 3.
+"""
+
+# from pprint import pprint as pp
+import csv
+import datetime
+import optparse
+import re
+import subprocess
+import sys
+import tempfile
+# import warnings
+
+def parse_options():
+    parser = optparse.OptionParser(usage=USAGE, version=VERSION)
+    opts, args = parser.parse_args()
+    if len(args) > 2:
+        parser.print_help()
+        sys.exit()
+    return opts, args
+
+def single_space(ms):
+    if ms is not None: ms = re.sub(r'  +',' ',ms)
+    return ms
+
+# Join two strings with the give separator, but omit the separator
+# if either string is empty.
+def intercalate2(sep,astr,bstr):
+    if astr and bstr:
+        return astr + sep + bstr
+    else:
+        return astr + bstr
+
+def main():
+    opts, args = parse_options()
+    out = open(args[1],'w') if len(args) > 1 else sys.stdout
+    with open(args[0],'r') if len(args) > 0 else sys.stdin as csvfile:
+
+        # Process CSV records, and generate a hledger journal entry for each transaction.
+
+        for r in csv.reader(csvfile):
+
+            # skip headings (record containing no numbers)
+            if all(map(lambda v: not any(c.isdigit() for c in v), r)): continue
+
+            # hledger doesn't like records with only one field
+            if len(r) < 2: continue
+
+            # skip non-transaction records
+            if re.match(r'^(Starting Balance|Net Change|Total|)$',r[0]): continue
+            
+            # write a hledger journal entry
+            property_,date_,payee_payer_,type_,reference_,debit_,credit_,balance_,description_,gl_account_ = r
+            date         = datetime.datetime.strptime(date_,"%m/%d/%Y").date().isoformat()
+            code         = f" ({reference_})" if reference_ else ""
+            description  = intercalate2(' | ', payee_payer_, intercalate2(' ', description_, type_))
+            amount1      = f"${debit_}" if debit_ else ""
+            amount2      = f"${credit_}" if credit_ else ""
+            balance1     = balance_
+            account1     = f"Properties:{property_}"
+            if gl_account_[0].isdigit():
+                account2 = f"{gl_account_[0]}xxx:{gl_account_}"
+            else:
+                account2 = f"{gl_account_}"
+            account1, account2 = single_space(account1), single_space(account2)
+            out.write(f"""\
+{date}{code} {description}
+    {account1}    {amount1} ; = {balance1}
+    {account2}    {amount2}
+
+""")
+
+if __name__ == "__main__": main()