gh-41103: some python-style for loops in rings/padics
    
convert some loops in `rings/padics` to the python-style syntax

### 📝 Checklist

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
    
URL: #41103
Reported by: Frédéric Chapoton
Reviewer(s): David Coudert

Author: Release Manager

src/sage/rings/padics/padic_ZZ_pX_CA_element.pyx

@@ -332,10 +332,8 @@ cdef class pAdicZZpXCAElement(pAdicZZpXElement):
                 x = Rational(x)
             elif x.type() == 't_POLMOD' or x.type == 't_POL':
                 # This code doesn't check to see if the primes are the same.
-                L = []
                 x = x.lift().lift()
-                for i from 0 <= i <= x.poldegree():
-                    L.append(Integer(x.polcoef(i)))
+                L = [Integer(x.polcoef(i)) for i in range(x.poldegree() + 1)]
                 x = L
             else:
                 raise TypeError("unsupported coercion from pari: only p-adics, integers, rationals, polynomials and pol_mods allowed")
@@ -1300,7 +1298,7 @@ cdef class pAdicZZpXCAElement(pAdicZZpXElement):
             # checks to see if the residue of self's unit is in the prime field.
             if self.prime_pow.e == 1:
                 unit = self.unit_part()
-                for i from 1 <= i <= ZZ_pX_deg(unit.value):
+                for i in range(1, ZZ_pX_deg(unit.value) + 1):
                     if not ZZ_divide_test(ZZ_p_rep(ZZ_pX_coeff(unit.value, i)), self.prime_pow.pow_ZZ_tmp(1)[0]):
                         raise ValueError("in order to raise to a p-adic exponent, base must reduce to an element of F_p mod the uniformizer")
             # compute the "level"

src/sage/rings/padics/padic_ZZ_pX_CR_element.pyx

@@ -346,10 +346,8 @@ cdef class pAdicZZpXCRElement(pAdicZZpXElement):
                 x = Rational(x)
             elif x.type() == 't_POLMOD' or x.type == 't_POL':
                 # This code doesn't check to see if the primes are the same.
-                L = []
                 x = x.lift().lift()
-                for i from 0 <= i <= x.poldegree():
-                    L.append(Integer(x.polcoef(i)))
+                L = [Integer(x.polcoef(i)) for i in range(x.poldegree() + 1)]
                 x = L
             else:
                 raise TypeError("unsupported coercion from pari: only p-adics, integers, rationals, polynomials and pol_mods allowed")
@@ -1974,7 +1972,7 @@ cdef class pAdicZZpXCRElement(pAdicZZpXElement):
                 raise NotImplementedError("negative valuation exponents not yet supported")
             # checks to see if the residue of self.unit is in the prime field.
             if self.prime_pow.e == 1:
-                for i from 1 <= i <= ZZ_pX_deg(self.unit):
+                for i in range(ZZ_pX_deg(self.unit) + 1):
                     if not ZZ_divide_test(ZZ_p_rep(ZZ_pX_coeff(self.unit, i)), self.prime_pow.pow_ZZ_tmp(1)[0]):
                         raise ValueError("in order to raise to a p-adic exponent, base must reduce to an element of F_p mod the uniformizer")
             # compute the "level"

src/sage/rings/padics/padic_ZZ_pX_FM_element.pyx

@@ -225,10 +225,8 @@ cdef class pAdicZZpXFMElement(pAdicZZpXElement):
                 x = Rational(x)
             elif x.type() == 't_POLMOD' or x.type == 't_POL':
                 # This code doesn't check to see if the primes are the same.
-                L = []
                 x = x.lift().lift()
-                for i from 0 <= i <= x.poldegree():
-                    L.append(Integer(x.polcoef(i)))
+                L = [Integer(x.polcoef(i)) for i in range(x.poldegree() + 1)]
                 x = L
             else:
                 raise TypeError("unsupported coercion from pari: only p-adics, integers, rationals, polynomials and pol_mods allowed")

src/sage/rings/padics/padic_ZZ_pX_element.pyx

@@ -296,18 +296,18 @@ cdef class pAdicZZpXElement(pAdicExtElement):
         #print(printer)
 
         if self.prime_pow.e == 1:
-            for j from 0 <= j < self.prime_pow.prec_cap:
+            for j in range(self.prime_pow.prec_cap):
                 ans.append([])
-            for i from 0 <= i < self.prime_pow.deg:
+            for i in range(self.prime_pow.deg):
                 ZZ_coeff.x = ZZ_p_rep(ZZ_pX_coeff(shifter, i))
                 ZZ_to_mpz(coeff.value, &ZZ_coeff.x)
                 L = printer.base_p_list(coeff, pos)
-                for j from 0 <= j < prec:
+                for j in range(prec):
                     if j < len(L):
                         ans[j].append(L[j])
                     else:
                         ans[j].append(zero)
-            for j from 0 <= j < prec:
+            for j in range(prec):
                 while ans[j]:
                     if ans[j][-1] == 0:
                         ans[j].pop()
@@ -322,7 +322,7 @@ cdef class pAdicZZpXElement(pAdicExtElement):
                 # It's important that one doesn't normalize in between shifting (for capped relative elements):
                 # _const_term doesn't normalize and thus we pick up the zeros
                 # since we're throwing away leading zeros, it doesn't matter if we start normalized or not.
-                for j from 0 <= j < self.prime_pow.e:
+                for j in range(self.prime_pow.e):
                     list_elt = PY_NEW(Integer)
                     if i + j == prec:
                         break
@@ -655,7 +655,7 @@ cdef preprocess_list(pAdicZZpXElement elt, L):
         pshift_z = ntl_ZZ.__new__(ntl_ZZ)
         pshift_z.x = elt.prime_pow.pow_ZZ_tmp(-mpz_get_si((<Integer>min_val).value))[0]
         pshift_m = elt.prime_pow.pow_Integer(-mpz_get_si((<Integer>min_val).value))
-        for i from 0 <= i < len(L):
+        for i in range(len(L)):
             if isinstance(L[i], ntl_ZZ):
                 L[i] = ntl_ZZ_p(L[i]*pshift_z, ctx)
             elif isinstance(L[i], (Integer, Rational, int)):
@@ -670,7 +670,7 @@ cdef preprocess_list(pAdicZZpXElement elt, L):
         pshift_z = ntl_ZZ.__new__(ntl_ZZ)
         pshift_z.x = elt.prime_pow.pow_ZZ_tmp(mpz_get_ui((<Integer>min_val).value))[0]
         pshift_m = elt.prime_pow.pow_Integer(mpz_get_ui((<Integer>min_val).value))
-        for i from 0 <= i < len(L):
+        for i in range(len(L)):
             if isinstance(L[i], ntl_ZZ):
                 ZZ_div(tmp, (<ntl_ZZ>L[i]).x, pshift_z.x)
                 py_tmp = ntl_ZZ.__new__(ntl_ZZ)
@@ -688,7 +688,7 @@ cdef preprocess_list(pAdicZZpXElement elt, L):
                 py_tmp.x = tmp
                 L[i] = ntl_ZZ_p(py_tmp, ctx)
     else:
-        for i from 0 <= i < len(L):
+        for i in range(len(L)):
             if isinstance(L[i], (ntl_ZZ, Integer, Rational, int)):
                 L[i] = ntl_ZZ_p(L[i], ctx)
             elif (isinstance(L[i], pAdicGenericElement) and L[i]._is_base_elt(elt.prime_pow.prime)) or isinstance(L[i], IntegerMod_abstract) or (L[i].modulus_context() is not ctx):
@@ -754,7 +754,7 @@ cdef find_val_aprec(PowComputer_ext pp, L):
     min_val = big
     min_aprec = big
     total_type = two # we begin by defaulting to the list elements being integers
-    for i from 0 <= i < len(L):
+    for i in range(len(L)):
         cur_val, cur_aprec, cur_type = get_val_prec(pp, L[i])
         #return "a","b","c"
         # proc_type == 0 indicates something with finite precision

src/sage/rings/padics/padic_printing.pyx

@@ -1173,7 +1173,7 @@ cdef class pAdicPrinter_class(SageObject):
                     else:
                         pk = Integer(1)
                         integral = True
-                    for i from 0 <= i < len(L):
+                    for i in range(len(L)):
                         if L[i] != "":
                             a = Integer(L[i])
                             if not pos and 2*a > pn:
@@ -1220,7 +1220,7 @@ cdef class pAdicPrinter_class(SageObject):
                     if self.unram_name is None:
                         raise RuntimeError("need to have specified a name for the unramified variable")
                     L, ellipsis = self._truncate_list(L, self.max_ram_terms, [])
-                    for i from 0 <= i < len(L):
+                    for i in range(len(L)):
                         unram_name = self.latex_unram_name if do_latex else self.unram_name
                         term = self._print_unram_term(L[i], do_latex, unram_name, self.max_unram_terms, 0, 0)
                         if len(term) > 0:
@@ -1393,7 +1393,7 @@ cdef class pAdicPrinter_class(SageObject):
         cdef Py_ssize_t j, newj
         cdef long exp, count = 0
         if increasing:
-            for j from 0 <= j < len(L):
+            for j in range(len(L)):
                 exp = j + expshift
                 if L[j] != 0:
                     if max_unram_terms == 0:
@@ -1480,7 +1480,7 @@ cdef class pAdicPrinter_class(SageObject):
         cdef Py_ssize_t j
         cdef long exp
         if increasing:
-            for j from 0 <= j < len(L):
+            for j in range(len(L)):
                 exp = j + expshift
                 s = self._print_term_of_poly(s, L[j], do_latex, polyname, exp)
         else: