diff --git a/lib/matrix.gi b/lib/matrix.gi
index 121fea57f1..3d96fba054 100644
--- a/lib/matrix.gi
+++ b/lib/matrix.gi
@@ -1489,7 +1489,7 @@ InstallMethod( DeterminantMatDestructive,
 
             # make its row the current row
             if i <> j  then
-                row := mat[j];  mat[j] := mat[i];  mat[i] := row;
+                SwapMatrixRows(mat, j, i);
                 sgn := -sgn;
             else
                 row := mat[j];
@@ -1566,9 +1566,7 @@ function( mat )
 
             # ... make its row the current row, ...
             if k <> j then
-                row    := mat[j];
-                mat[j] := mat[k];
-                mat[k] := row;
+                SwapMatrixRows(mat, j, k);
                 sgn    := -sgn;
             else
                 row := mat[j];
@@ -1789,30 +1787,20 @@ local R,M,transform,divide,swaprow, swapcol, addcol, addrow, multcol, multrow, l
 
   swaprow:=function(a,b)
   local r;
-    r:=M[a];
-    M[a]:=M[b];
-    M[b]:=r;
+    SwapMatrixRows(M, a, b);
     if transform then
-      r:=left[a];
-      left[a]:=left[b];
-      left[b]:=r;
+      SwapMatrixRows(left, a, b);
       if basmat<>fail then
-        r:=basmat[a];
-        basmat[a]:=basmat[b];
-        basmat[b]:=r;
+        SwapMatrixRows(basmat, a, b);
       fi;
     fi;
   end;
 
   swapcol:=function(a,b)
   local c;
-    c:=M{[1..l]}[a];
-    M{[1..l]}[a]:=M{[1..l]}[b];
-    M{[1..l]}[b]:=c;
+    SwapMatrixColumns(M, a, b);
     if transform then
-      c:=right{[1..n]}[a];
-      right{[1..n]}[a]:=right{[1..n]}[b];
-      right{[1..n]}[b]:=c;
+      SwapMatrixColumns(right, a, b);
     fi;
   end;
 
diff --git a/lib/zlattice.gi b/lib/zlattice.gi
index d4204340b7..95e203cecd 100644
--- a/lib/zlattice.gi
+++ b/lib/zlattice.gi
@@ -195,9 +195,7 @@ InstallGlobalFunction( LinearIndependentColumns, function( mat )
             fi;
 
             # Swap rows `j' and `i'.
-            row:= mat[j];
-            mat[j]:= mat[i];
-            mat[i]:= row;
+            SwapMatrixRows(mat, i, j);
 
             # Normalize column `k'.
             val:= row[k];