diff --git a/reframe/core/schedulers/slurm.py b/reframe/core/schedulers/slurm.py
index 240ea1beb..1a4d404fb 100644
--- a/reframe/core/schedulers/slurm.py
+++ b/reframe/core/schedulers/slurm.py
@@ -734,11 +734,10 @@ def satisfies(self, slurm_constraint: str):
                  for grp in re.finditer(r'(\w(\w|\d)*)', slurm_constraint)}
         slurm_constraint = slurm_constraint.replace(
             "&", " and ").replace("|", " or ")
-        expr = " ".join([f"vars['{key}']" if key not in [
-                        'and', 'or'
-                        ] else key
-            for key in slurm_constraint.split()])
-
+        # Pattern to extract the variable names
+        pattern = r'\b(?!and\b|or\b)(\d*[a-zA-Z_]\w*)\b'
+        # Replace each variable with var['variable']
+        expr = re.sub(pattern, r"vars['\1']", slurm_constraint)
         vars = {n: True for n in self.active_features}
         vars.update({n: False for n in names - self.active_features})
         try:
diff --git a/requirements.txt b/requirements.txt
index 180c75339..1f2235de0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,6 @@ archspec==0.2.5
 argcomplete==3.1.2; python_version < '3.8'
 argcomplete==3.5.1; python_version >= '3.8'
 autopep8==2.0.4
-autopep8==2.0.4
 filelock==3.4.1; python_version == '3.6'
 filelock==3.12.2; python_version == '3.7'
 filelock==3.16.1; python_version >= '3.8'
diff --git a/setup.cfg b/setup.cfg
index 642a277bc..690a0c21c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -29,6 +29,7 @@ install_requires =
     archspec >= 0.2.4
     argcomplete
     argcomplete <= 3.1.2; python_version < '3.8'
+    autopep8
     filelock
     filelock<=3.12.2; python_version == '3.7'
     filelock<=3.4.1; python_version == '3.6'