Identify which strikes to use for entering an iron condor based on a target delta

iron_condor.py

@@ -1,18 +1,19 @@
 from datetime import datetime
 from dotenv import load_dotenv
 from ibkr import Client
+from ibkr.option_type import CALL, PUT
 from os import getenv
 from tastytrade import Tastytrade
 
 load_dotenv()
 
-ibkr_host = getenv("IBKR_HOST")
-ibkr_port = getenv("IBKR_PORT")
+ibkr_host = getenv('IBKR_HOST')
+ibkr_port = getenv('IBKR_PORT')
 ibkr_client = Client(host = ibkr_host, port = ibkr_port)
 
-tastytrade_account = getenv("TASTYTRADE_ACCOUNT")
-tastytrade_username = getenv("TASTYTRADE_USERNAME")
-tastytrade_password = getenv("TASTYTRADE_PASSWORD")
+tastytrade_account = getenv('TASTYTRADE_ACCOUNT')
+tastytrade_username = getenv('TASTYTRADE_USERNAME')
+tastytrade_password = getenv('TASTYTRADE_PASSWORD')
 tastytrade_client = Tastytrade(tastytrade_username, tastytrade_password)
 tastytrade_client.login()
 
@@ -28,4 +29,33 @@ def contract_filter(contract):
 
 # The weekly symbol for SPX (SPXW) is required in order to distinguish from monthly options.
 option_chain = ibkr_client.get_option_chain('SPX', datetime.now(), sub_symbol = 'SPXW', contract_filter = contract_filter)
-print(option_chain)
+print(option_chain)
+
+target_delta = 0.10
+
+def closest_strike_by_delta(target_delta, option_chain, option_type):
+    options = option_chain[option_chain['Type'] == option_type].copy()
+    options['Delta Distance'] = abs(options['Delta'] - (target_delta * (1 if option_type == CALL else -1)))
+    return options.loc[options['Delta Distance'].idxmin()]
+
+# Find the strikes that minimize the distance to the target delta.
+closest_call_strike = closest_strike_by_delta(target_delta, option_chain, CALL)
+closest_put_strike = closest_strike_by_delta(target_delta, option_chain, PUT)
+
+# Do the same for the long strikes.
+target_long_call_strike = closest_call_strike['Strike'] + 50
+target_long_put_strike = closest_put_strike['Strike'] - 50
+
+def closest_strike_by_strike(target_strike, option_chain, option_type):
+    options = option_chain[option_chain['Type'] == option_type].copy()
+    options['Strike Distance'] = abs(options['Strike'] - target_strike)
+    return options.loc[options['Strike Distance'].idxmin()]
+
+closest_long_call_strike = closest_strike_by_strike(target_long_call_strike, option_chain, CALL)
+closest_long_put_strike = closest_strike_by_strike(target_long_put_strike, option_chain, PUT)
+
+# The requested iron condor.
+print('Short Call Strike:', closest_call_strike['Strike'])
+print('Long Call Strike:', closest_long_call_strike['Strike'])
+print("Short Put Strike:", closest_put_strike['Strike'])
+print('Long Put Strike:', closest_long_put_strike['Strike'])