Python 列表理解是通过 map 和 lambda 函数实现的吗

不，列表理解不是由map和lambda在引擎盖下实现的，也不是在CPython和Pypy3中实现的.

CPython (3.9.13 here) compiles the list comprehension into a special code object that outputs a list并将其作为函数调用:

~ $ echo 'x = [a + 1 for a in [1, 2, 3, 4]]' | python3 -m dis
  1           0 LOAD_CONST               0 (<code object <listcomp> at 0x107446f50, file "<stdin>", line 1>)
              2 LOAD_CONST               1 ('<listcomp>')
              4 MAKE_FUNCTION            0
              6 LOAD_CONST               2 ((1, 2, 3, 4))
              8 GET_ITER
             10 CALL_FUNCTION            1
             12 STORE_NAME               0 (x)
             14 LOAD_CONST               3 (None)
             16 RETURN_VALUE

Disassembly of <code object <listcomp> at 0x107446f50, file "<stdin>", line 1>:
  1           0 BUILD_LIST               0
              2 LOAD_FAST                0 (.0)
        >>    4 FOR_ITER                12 (to 18)
              6 STORE_FAST               1 (a)
              8 LOAD_FAST                1 (a)
             10 LOAD_CONST               0 (1)
             12 BINARY_ADD
             14 LIST_APPEND              2
             16 JUMP_ABSOLUTE            4
        >>   18 RETURN_VALUE

然而，等价的list(map(lambda: ...))件事只是函数调用:

~ $ echo 'x = list(map(lambda a: a + 1, [1, 2, 3, 4]))' | python3 -m dis
  1           0 LOAD_NAME                0 (list)
              2 LOAD_NAME                1 (map)
              4 LOAD_CONST               0 (<code object <lambda> at 0x102701f50, file "<stdin>", line 1>)
              6 LOAD_CONST               1 ('<lambda>')
              8 MAKE_FUNCTION            0
             10 BUILD_LIST               0
             12 LOAD_CONST               2 ((1, 2, 3, 4))
             14 LIST_EXTEND              1
             16 CALL_FUNCTION            2
             18 CALL_FUNCTION            1
             20 STORE_NAME               2 (x)
             22 LOAD_CONST               3 (None)
             24 RETURN_VALUE

Disassembly of <code object <lambda> at 0x102701f50, file "<stdin>", line 1>:
  1           0 LOAD_FAST                0 (a)
              2 LOAD_CONST               1 (1)
              4 BINARY_ADD
              6 RETURN_VALUE