Updated files in polynomial/ to use fstrings

10 files changed, 61 insertions, 68 deletions

diff --git a/numpy/polynomial/_polybase.py b/numpy/polynomial/_polybase.py
index 28bd50ec6..3e16e8d8c 100644
--- a/numpy/polynomial/_polybase.py
+++ b/numpy/polynomial/_polybase.py
@@ -277,18 +277,16 @@ class ABCPolyBase(abc.ABC):
             self.window = window
 
     def __repr__(self):
-        format = "%s(%s, domain=%s, window=%s)"
         coef = repr(self.coef)[6:-1]
         domain = repr(self.domain)[6:-1]
         window = repr(self.window)[6:-1]
         name = self.__class__.__name__
-        return format % (name, coef, domain, window)
+        return f"{name}({coef}, domain={domain}, window={window})"
 
     def __str__(self):
-        format = "%s(%s)"
         coef = str(self.coef)
         name = self.nickname
-        return format % (name, coef)
+        return f"{name}({coef})"
 
     @classmethod
     def _repr_latex_term(cls, i, arg_str, needs_parens):
@@ -297,9 +295,7 @@ class ABCPolyBase(abc.ABC):
                 "Subclasses must define either a basis name, or override "
                 "_repr_latex_term(i, arg_str, needs_parens)")
         # since we always add parens, we don't care if the expression needs them
-        return "{{{basis}}}_{{{i}}}({arg_str})".format(
-            basis=cls.basis_name, i=i, arg_str=arg_str
-        )
+        return f"{{{cls.basis_name}}}_{{{i}}}({arg_str})"
 
     @staticmethod
     def _repr_latex_scalar(x):
@@ -314,19 +310,15 @@ class ABCPolyBase(abc.ABC):
             term = 'x'
             needs_parens = False
         elif scale == 1:
-            term = '{} + x'.format(
-                self._repr_latex_scalar(off)
-            )
+            term = f"{self._repr_latex_scalar(off)} + x"
             needs_parens = True
         elif off == 0:
-            term = '{}x'.format(
-                self._repr_latex_scalar(scale)
-            )
+            term = f"{self._repr_latex_scalar(scale)}x"
             needs_parens = True
         else:
-            term = '{} + {}x'.format(
-                self._repr_latex_scalar(off),
-                self._repr_latex_scalar(scale)
+            term = (
+                f"{self._repr_latex_scalar(off)} + "
+                f"{self._repr_latex_scalar(scale)}x"
             )
             needs_parens = True
 
@@ -336,20 +328,20 @@ class ABCPolyBase(abc.ABC):
         for i, c in enumerate(self.coef):
             # prevent duplication of + and - signs
             if i == 0:
-                coef_str = '{}'.format(self._repr_latex_scalar(c))
+                coef_str = f"{self._repr_latex_scalar(c)}"
             elif not isinstance(c, numbers.Real):
-                coef_str = ' + ({})'.format(self._repr_latex_scalar(c))
+                coef_str = f" + ({self._repr_latex_scalar(c)})"
             elif not np.signbit(c):
-                coef_str = ' + {}'.format(self._repr_latex_scalar(c))
+                coef_str = f" + {self._repr_latex_scalar(c)}"
             else:
-                coef_str = ' - {}'.format(self._repr_latex_scalar(-c))
+                coef_str = f" - {self._repr_latex_scalar(-c)}"
 
             # produce the string for the term
             term_str = self._repr_latex_term(i, term, needs_parens)
             if term_str == '1':
                 part = coef_str
             else:
-                part = r'{}\,{}'.format(coef_str, term_str)
+                part = rf"{coef_str}\,{term_str}"
 
             if c == 0:
                 part = mute(part)
@@ -362,7 +354,7 @@ class ABCPolyBase(abc.ABC):
             # in case somehow there are no coefficients at all
             body = '0'
 
-        return r'$x \mapsto {}$'.format(body)
+        return rf"$x \mapsto {body}$"
 
 
 
@@ -432,8 +424,10 @@ class ABCPolyBase(abc.ABC):
         # could return the first n elements of an infinite series.
         # It is hard to see where n would come from, though.
         if not isinstance(other, numbers.Number) or isinstance(other, bool):
-            form = "unsupported types for true division: '%s', '%s'"
-            raise TypeError(form % (type(self), type(other)))
+            raise TypeError(
+                f"unsupported types for true division: "
+                f"'{type(self)}', '{type(other)}'"
+            )
         return self.__floordiv__(other)
 
     def __floordiv__(self, other):
diff --git a/numpy/polynomial/polynomial.py b/numpy/polynomial/polynomial.py
index 94c722628..97f66a152 100644
--- a/numpy/polynomial/polynomial.py
+++ b/numpy/polynomial/polynomial.py
@@ -1481,10 +1481,10 @@ class Polynomial(ABCPolyBase):
     @staticmethod
     def _repr_latex_term(i, arg_str, needs_parens):
         if needs_parens:
-            arg_str = r'\left({}\right)'.format(arg_str)
+            arg_str = rf"\left({arg_str}\right)"
         if i == 0:
             return '1'
         elif i == 1:
             return arg_str
         else:
-            return '{}^{{{}}}'.format(arg_str, i)
+            return f"{arg_str}^{{{i}}}"
diff --git a/numpy/polynomial/polyutils.py b/numpy/polynomial/polyutils.py
index 9b8e9fc42..ec7ba6f1d 100644
--- a/numpy/polynomial/polyutils.py
+++ b/numpy/polynomial/polyutils.py
@@ -468,10 +468,10 @@ def _vander_nd(vander_fs, points, degrees):
     n_dims = len(vander_fs)
     if n_dims != len(points):
         raise ValueError(
-            "Expected {} dimensions of sample points, got {}".format(n_dims, len(points)))
+            f"Expected {n_dims} dimensions of sample points, got {len(points)}")
     if n_dims != len(degrees):
         raise ValueError(
-            "Expected {} dimensions of degrees, got {}".format(n_dims, len(degrees)))
+            f"Expected {n_dims} dimensions of degrees, got {len(degrees)}")
     if n_dims == 0:
         raise ValueError("Unable to guess a dtype or shape when no points are given")
 
@@ -786,12 +786,11 @@ def _deprecate_as_int(x, desc):
         else:
             if ix == x:
                 warnings.warn(
-                    "In future, this will raise TypeError, as {} will need to "
-                    "be an integer not just an integral float."
-                    .format(desc),
+                    f"In future, this will raise TypeError, as {desc} will "
+                    "need to be an integer not just an integral float.",
                     DeprecationWarning,
                     stacklevel=3
                 )
                 return ix
 
-        raise TypeError("{} must be an integer".format(desc))
+        raise TypeError(f"{desc} must be an integer")
diff --git a/numpy/polynomial/tests/test_chebyshev.py b/numpy/polynomial/tests/test_chebyshev.py
index ec0a7839a..2f54bebfd 100644
--- a/numpy/polynomial/tests/test_chebyshev.py
+++ b/numpy/polynomial/tests/test_chebyshev.py
@@ -65,7 +65,7 @@ class TestArithmetic:
     def test_chebadd(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] += 1
@@ -75,7 +75,7 @@ class TestArithmetic:
     def test_chebsub(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] -= 1
@@ -93,7 +93,7 @@ class TestArithmetic:
     def test_chebmul(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(i + j + 1)
                 tgt[i + j] += .5
                 tgt[abs(i - j)] += .5
@@ -103,7 +103,7 @@ class TestArithmetic:
     def test_chebdiv(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 ci = [0]*i + [1]
                 cj = [0]*j + [1]
                 tgt = cheb.chebadd(ci, cj)
@@ -114,7 +114,7 @@ class TestArithmetic:
     def test_chebpow(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 c = np.arange(i + 1)
                 tgt = reduce(cheb.chebmul, [c]*j, np.array([1]))
                 res = cheb.chebpow(c, j)
@@ -139,7 +139,7 @@ class TestEvaluation:
         x = np.linspace(-1, 1)
         y = [polyval(x, c) for c in Tlist]
         for i in range(10):
-            msg = "At i=%d" % i
+            msg = f"At i={i}"
             tgt = y[i]
             res = cheb.chebval(x, [0]*i + [1])
             assert_almost_equal(res, tgt, err_msg=msg)
diff --git a/numpy/polynomial/tests/test_classes.py b/numpy/polynomial/tests/test_classes.py
index 68656bc98..a2682bd36 100644
--- a/numpy/polynomial/tests/test_classes.py
+++ b/numpy/polynomial/tests/test_classes.py
@@ -42,7 +42,7 @@ def assert_poly_almost_equal(p1, p2, msg=""):
         assert_(np.all(p1.window == p2.window))
         assert_almost_equal(p1.coef, p2.coef)
     except AssertionError:
-        msg = "Result: %s\nTarget: %s", (p1, p2)
+        msg = f"Result: {p1}\nTarget: {p2}"
         raise AssertionError(msg)
 
 
diff --git a/numpy/polynomial/tests/test_hermite.py b/numpy/polynomial/tests/test_hermite.py
index 4b67c1b18..53ee0844e 100644
--- a/numpy/polynomial/tests/test_hermite.py
+++ b/numpy/polynomial/tests/test_hermite.py
@@ -49,7 +49,7 @@ class TestArithmetic:
     def test_hermadd(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] += 1
@@ -59,7 +59,7 @@ class TestArithmetic:
     def test_hermsub(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] -= 1
@@ -80,7 +80,7 @@ class TestArithmetic:
             pol1 = [0]*i + [1]
             val1 = herm.hermval(self.x, pol1)
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 pol2 = [0]*j + [1]
                 val2 = herm.hermval(self.x, pol2)
                 pol3 = herm.hermmul(pol1, pol2)
@@ -91,7 +91,7 @@ class TestArithmetic:
     def test_hermdiv(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 ci = [0]*i + [1]
                 cj = [0]*j + [1]
                 tgt = herm.hermadd(ci, cj)
@@ -102,7 +102,7 @@ class TestArithmetic:
     def test_hermpow(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 c = np.arange(i + 1)
                 tgt = reduce(herm.hermmul, [c]*j, np.array([1]))
                 res = herm.hermpow(c, j) 
@@ -127,7 +127,7 @@ class TestEvaluation:
         x = np.linspace(-1, 1)
         y = [polyval(x, c) for c in Hlist]
         for i in range(10):
-            msg = "At i=%d" % i
+            msg = f"At i={i}"
             tgt = y[i]
             res = herm.hermval(x, [0]*i + [1])
             assert_almost_equal(res, tgt, err_msg=msg)
diff --git a/numpy/polynomial/tests/test_hermite_e.py b/numpy/polynomial/tests/test_hermite_e.py
index 3052500cc..2d262a330 100644
--- a/numpy/polynomial/tests/test_hermite_e.py
+++ b/numpy/polynomial/tests/test_hermite_e.py
@@ -49,7 +49,7 @@ class TestArithmetic:
     def test_hermeadd(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] += 1
@@ -59,7 +59,7 @@ class TestArithmetic:
     def test_hermesub(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] -= 1
@@ -80,7 +80,7 @@ class TestArithmetic:
             pol1 = [0]*i + [1]
             val1 = herme.hermeval(self.x, pol1)
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 pol2 = [0]*j + [1]
                 val2 = herme.hermeval(self.x, pol2)
                 pol3 = herme.hermemul(pol1, pol2)
@@ -91,7 +91,7 @@ class TestArithmetic:
     def test_hermediv(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 ci = [0]*i + [1]
                 cj = [0]*j + [1]
                 tgt = herme.hermeadd(ci, cj)
@@ -102,7 +102,7 @@ class TestArithmetic:
     def test_hermepow(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 c = np.arange(i + 1)
                 tgt = reduce(herme.hermemul, [c]*j, np.array([1]))
                 res = herme.hermepow(c, j)
@@ -127,7 +127,7 @@ class TestEvaluation:
         x = np.linspace(-1, 1)
         y = [polyval(x, c) for c in Helist]
         for i in range(10):
-            msg = "At i=%d" % i
+            msg = f"At i={i}"
             tgt = y[i]
             res = herme.hermeval(x, [0]*i + [1])
             assert_almost_equal(res, tgt, err_msg=msg)
diff --git a/numpy/polynomial/tests/test_laguerre.py b/numpy/polynomial/tests/test_laguerre.py
index ec103c258..227ef3c55 100644
--- a/numpy/polynomial/tests/test_laguerre.py
+++ b/numpy/polynomial/tests/test_laguerre.py
@@ -46,7 +46,7 @@ class TestArithmetic:
     def test_lagadd(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] += 1
@@ -56,7 +56,7 @@ class TestArithmetic:
     def test_lagsub(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] -= 1
@@ -77,7 +77,7 @@ class TestArithmetic:
             pol1 = [0]*i + [1]
             val1 = lag.lagval(self.x, pol1)
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 pol2 = [0]*j + [1]
                 val2 = lag.lagval(self.x, pol2)
                 pol3 = lag.lagmul(pol1, pol2)
@@ -88,7 +88,7 @@ class TestArithmetic:
     def test_lagdiv(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 ci = [0]*i + [1]
                 cj = [0]*j + [1]
                 tgt = lag.lagadd(ci, cj)
@@ -99,7 +99,7 @@ class TestArithmetic:
     def test_lagpow(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 c = np.arange(i + 1)
                 tgt = reduce(lag.lagmul, [c]*j, np.array([1]))
                 res = lag.lagpow(c, j) 
@@ -124,7 +124,7 @@ class TestEvaluation:
         x = np.linspace(-1, 1)
         y = [polyval(x, c) for c in Llist]
         for i in range(7):
-            msg = "At i=%d" % i
+            msg = f"At i={i}"
             tgt = y[i]
             res = lag.lagval(x, [0]*i + [1])
             assert_almost_equal(res, tgt, err_msg=msg)
diff --git a/numpy/polynomial/tests/test_legendre.py b/numpy/polynomial/tests/test_legendre.py
index 8846ca6f2..a2a212c24 100644
--- a/numpy/polynomial/tests/test_legendre.py
+++ b/numpy/polynomial/tests/test_legendre.py
@@ -49,7 +49,7 @@ class TestArithmetic:
     def test_legadd(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] += 1
@@ -59,7 +59,7 @@ class TestArithmetic:
     def test_legsub(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] -= 1
@@ -81,7 +81,7 @@ class TestArithmetic:
             pol1 = [0]*i + [1]
             val1 = leg.legval(self.x, pol1)
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 pol2 = [0]*j + [1]
                 val2 = leg.legval(self.x, pol2)
                 pol3 = leg.legmul(pol1, pol2)
@@ -92,7 +92,7 @@ class TestArithmetic:
     def test_legdiv(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 ci = [0]*i + [1]
                 cj = [0]*j + [1]
                 tgt = leg.legadd(ci, cj)
@@ -103,7 +103,7 @@ class TestArithmetic:
     def test_legpow(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 c = np.arange(i + 1)
                 tgt = reduce(leg.legmul, [c]*j, np.array([1]))
                 res = leg.legpow(c, j) 
@@ -128,7 +128,7 @@ class TestEvaluation:
         x = np.linspace(-1, 1)
         y = [polyval(x, c) for c in Llist]
         for i in range(10):
-            msg = "At i=%d" % i
+            msg = f"At i={i}"
             tgt = y[i]
             res = leg.legval(x, [0]*i + [1])
             assert_almost_equal(res, tgt, err_msg=msg)
diff --git a/numpy/polynomial/tests/test_polynomial.py b/numpy/polynomial/tests/test_polynomial.py
index 50973c480..5fd1a82a2 100644
--- a/numpy/polynomial/tests/test_polynomial.py
+++ b/numpy/polynomial/tests/test_polynomial.py
@@ -47,7 +47,7 @@ class TestArithmetic:
     def test_polyadd(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] += 1
@@ -57,7 +57,7 @@ class TestArithmetic:
     def test_polysub(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(max(i, j) + 1)
                 tgt[i] += 1
                 tgt[j] -= 1
@@ -75,7 +75,7 @@ class TestArithmetic:
     def test_polymul(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 tgt = np.zeros(i + j + 1)
                 tgt[i + j] += 1
                 res = poly.polymul([0]*i + [1], [0]*j + [1])
@@ -94,7 +94,7 @@ class TestArithmetic:
         # check rest.
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 ci = [0]*i + [1, 2]
                 cj = [0]*j + [1, 2]
                 tgt = poly.polyadd(ci, cj)
@@ -105,7 +105,7 @@ class TestArithmetic:
     def test_polypow(self):
         for i in range(5):
             for j in range(5):
-                msg = "At i=%d, j=%d" % (i, j)
+                msg = f"At i={i}, j={j}"
                 c = np.arange(i + 1)
                 tgt = reduce(poly.polymul, [c]*j, np.array([1]))
                 res = poly.polypow(c, j)