add : chemical_formula attribute added.

opr/params.py

@@ -3,6 +3,38 @@
 OPR_VERSION = "0.1"
 VALID_BASES = set('ATCG')
 DNA_COMPLEMENT_MAP = {"A": "T", "C": "G", "G": "C", "T": "A"}
+CHEMICAL_FORMULA_BASES = {
+    'A': {
+        'C': 10,
+        'H': 13,
+        'N': 5,
+        'O': 3,
+    },
+    'T': {
+        'C': 10,
+        'H': 14,
+        'N': 2,
+        'O': 5,
+    },
+    'C': {
+        'C': 9,
+        'H': 13,
+        'N': 3,
+        'O': 4,
+    },
+    'G': {
+        'C': 10,
+        'H': 13,
+        'N': 5,
+        'O': 4,
+    },
+}
+CHEMICAL_FORMULA_WATER = {
+    'H': 2,
+    'O': 1,
+}
+CHEMICAL_FORMULA_FORMAT = "C{0}H{1}N{2}O{3}P{4}"
+CHEMICAL_FORMULA_FORMAT_SHORT = "C{0}H{1}N{2}O{3}"
 
 PRIMER_LOWER_LENGTH = 18
 PRIMER_HIGHEST_LENGTH = 30

opr/primer.py

@@ -14,7 +14,7 @@
 from .params import DNA_COMPLEMENT_MAP
 
 from .functions import molecular_weight_calc, basic_melting_temperature_calc
-from .functions import gc_content_calc
+from .functions import gc_content_calc, chemical_formula_calc
 
 
 class MeltingTemperature(Enum):
@@ -49,6 +49,7 @@ def __init__(self, sequence):
             MeltingTemperature.SALT_ADJUSTED: None,
             MeltingTemperature.NEAREST_NEIGHBOR: None,
         }
+        self._chemical_formula = None
 
     def __len__(self):
         """
@@ -200,6 +201,26 @@ def gc_content(self, _):
     @gc_content.deleter
     def gc_content(self, _):
         raise OPRBaseError(PRIMER_NOT_REMOVABLE_ATTRIBUTE_ERROR)
+
+    @property
+    def chemical_formula(self):
+        """
+        Calculate the chemical formula.
+
+        :return: chemical formula
+        """
+        if self._chemical_formula is not None:
+            return self._chemical_formula
+        self._chemical_formula = chemical_formula_calc(self._sequence)
+        return self._chemical_formula
+
+    @chemical_formula.setter
+    def chemical_formula(self, _):
+        raise OPRBaseError(PRIMER_READ_ONLY_ATTRIBUTE_ERROR)
+
+    @chemical_formula.deleter
+    def chemical_formula(self, _):
+        raise OPRBaseError(PRIMER_NOT_REMOVABLE_ATTRIBUTE_ERROR)
 
     def melting_temperature(self, method=MeltingTemperature.BASIC):
         """