diff --git a/Lib/_sre.py b/Lib/_sre.py
index 644ecef3a0..e498b89978 100644
--- a/Lib/_sre.py
+++ b/Lib/_sre.py
@@ -1155,17 +1155,17 @@ class _CharsetDispatcher(_Dispatcher):
             block_index = char_code >> 8
             # NB: there are CODESIZE block indices per bytecode
             a = array.array("B")
-            a.fromstring(array.array(CODESIZE == 2 and "H" or "I",
-                    [ctx.peek_code(block_index / CODESIZE)]).tostring())
+            a.frombytes(array.array(CODESIZE == 2 and "H" or "I",
+                    [ctx.peek_code(block_index // CODESIZE)]).tobytes())
             block = a[block_index % CODESIZE]
-            ctx.skip_code(256 / CODESIZE) # skip block indices
-            block_value = ctx.peek_code(block * (32 / CODESIZE)
+            ctx.skip_code(256 // CODESIZE) # skip block indices
+            block_value = ctx.peek_code(block * (32 // CODESIZE)
                     + ((char_code & 255) >> (CODESIZE == 2 and 4 or 5)))
             if block_value & (1 << (char_code & ((8 * CODESIZE) - 1))):
                 return self.ok
         else:
-            ctx.skip_code(256 / CODESIZE) # skip block indices
-        ctx.skip_code(count * (32 / CODESIZE)) # skip blocks
+            ctx.skip_code(256 // CODESIZE) # skip block indices
+        ctx.skip_code(count * (32 // CODESIZE)) # skip blocks
     def unknown(self, ctx):
         return False
 
diff --git a/vm/src/cformat.rs b/vm/src/cformat.rs
index e67fd07154..00aa4769b8 100644
--- a/vm/src/cformat.rs
+++ b/vm/src/cformat.rs
@@ -225,14 +225,13 @@ impl CFormatSpec {
             "-"
         };
 
-        // TODO: Support precision
         let magnitude_string = match self.format_type {
             CFormatType::Float(CFloatType::PointDecimal) => {
-                if Some(CFormatQuantity::Amount(6)) != self.precision {
-                    return Err("Not yet implemented for %#.#f types".to_string());
-                } else {
-                    format!("{:.6}", magnitude)
-                }
+                let precision = match self.precision {
+                    Some(CFormatQuantity::Amount(p)) => p,
+                    _ => 6,
+                };
+                format!("{:.*}", precision, magnitude)
             }
             CFormatType::Float(CFloatType::Exponent(_)) => {
                 return Err("Not yet implemented for %e and %E".to_string())