Python查看模块方法
Python是一种高级编程语言，具有简单易学、易读、易维护等特点。Python中有许多内置模块可以直接使用，同时也可以通过安装第三方模块来扩展Python的功能。在Python中，我们可以使用dir()函数来查看模块中的方法和属性。本文将介绍如何使用dir()函数来查看模块中的方法，并扩展相关问答。
_x000D_如何查看模块中的方法？
_x000D_在Python中，我们可以使用dir()函数来查看模块中的方法和属性。dir()函数可以接受一个对象作为参数，然后返回这个对象的所有属性和方法的名称列表。例如，我们可以使用以下代码来查看Python内置模块math中的所有方法和属性：
_x000D_ _x000D_import math
_x000D_print(dir(math))
_x000D_ _x000D_运行以上代码，我们可以看到输出结果为：
_x000D_ _x000D_['__doc__', '__loader__', '__name__', '__package__', '__spec__', 'acos', 'acosh', 'asin', 'asinh', 'atan', 'atan2', 'atanh', 'ceil', 'comb', 'copysign', 'cos', 'cosh', 'degrees', 'dist', 'e', 'erf', 'erfc', 'exp', 'expm1', 'fabs', 'factorial', 'floor', 'fmod', 'frexp', 'fsum', 'gamma', 'gcd', 'hypot', 'inf', 'isclose', 'isfinite', 'isinf', 'isnan', 'isqrt', 'ldexp', 'lgamma', 'log', 'log10', 'log1p', 'log2', 'modf', 'nan', 'perm', 'pi', 'pow', 'prod', 'radians', 'remainder', 'sin', 'sinh', 'sqrt', 'tan', 'tanh', 'tau', 'trunc']
_x000D_ _x000D_从输出结果中，我们可以看到math模块中的所有方法和属性，其中包括acos、asin、atan、ceil等方法。
_x000D_如何查看模块中的文档？
_x000D_在Python中，每个模块都有一个文档字符串（docstring），用于描述模块的功能和使用方法。我们可以使用help()函数来查看模块的文档字符串。例如，我们可以使用以下代码来查看Python内置模块math的文档字符串：
_x000D_ _x000D_import math
_x000D_help(math)
_x000D_ _x000D_运行以上代码，我们可以看到输出结果为：
_x000D_ _x000D_Help on module math:
_x000D_NAME
_x000D_math
_x000D_MODULE REFERENCE
_x000D_https://docs.python.org/3.9/library/math
_x000D_DESCRIPTION
_x000D_This module provides access to the mathematical functions
_x000D_defined by the C standard.
_x000D_FUNCTIONS
_x000D_acos(...)
_x000D_acos(x)
_x000D_Return the arc cosine (measured in radians) of x.
_x000D_acosh(...)
_x000D_acosh(x)
_x000D_Return the inverse hyperbolic cosine of x.
_x000D_asin(...)
_x000D_asin(x)
_x000D_Return the arc sine (measured in radians) of x.
_x000D_asinh(...)
_x000D_asinh(x)
_x000D_Return the inverse hyperbolic sine of x.
_x000D_atan(...)
_x000D_atan(x)
_x000D_Return the arc tangent (measured in radians) of x.
_x000D_atan2(...)
_x000D_atan2(y, x)
_x000D_Return the arc tangent (measured in radians) of y/x.
_x000D_Unlike atan(y/x), the signs of both x and y are considered.
_x000D_atanh(...)
_x000D_atanh(x)
_x000D_Return the inverse hyperbolic tangent of x.
_x000D_ceil(...)
_x000D_ceil(x)
_x000D_Return the ceiling of x as a float, the smallest integer value greater than or equal to x.
_x000D_comb(...)
_x000D_comb(N, k, exact=False)
_x000D_Return the number of ways to choose k items from N items without repetition and without order.
_x000D_copysign(...)
_x000D_copysign(x, y)
_x000D_Return a float with the magnitude (absolute value) of x but the sign of y. On platforms that support signed zeros, copysign(1.0,-0.0) returns -1.0.
_x000D_cos(...)
_x000D_cos(x)
_x000D_Return the cosine of x (measured in radians).
_x000D_cosh(...)
_x000D_cosh(x)
_x000D_Return the hyperbolic cosine of x.
_x000D_degrees(...)
_x000D_degrees(x)
_x000D_Convert angle x from radians to degrees.
_x000D_dist(...)
_x000D_dist(p, q)
_x000D_Return the Euclidean distance between two points p and q.
_x000D_e = 2.718281828459045
_x000D_erf(...)
_x000D_erf(x)
_x000D_Error function at x.
_x000D_erfc(...)
_x000D_erfc(x)
_x000D_Complementary error function at x.
_x000D_exp(...)
_x000D_exp(x)
_x000D_Return e raised to the power of x.
_x000D_expm1(...)
_x000D_expm1(x)
_x000D_Return exp(x) - 1. This function avoids the loss of precision involved in the direct evaluation of exp(x)-1 for small x.
_x000D_fabs(...)
_x000D_fabs(x)
_x000D_Return the absolute value of the float x.
_x000D_factorial(...)
_x000D_factorial(x, /) method of builtins.int instance
_x000D_factorial(x: int) -> int
_x000D_Find x!. Raise a ValueError if x is negative or non-integral.
_x000D_floor(...)
_x000D_floor(x)
_x000D_Return the floor of x as a float, the largest integer value less than or equal to x.
_x000D_fmod(...)
_x000D_fmod(x, y)
_x000D_Return fmod(x, y), according to platform C. x % y may differ.
_x000D_frexp(...)
_x000D_frexp(x)
_x000D_Return the mantissa and exponent of x as the pair (m, e).
_x000D_m is a float and e is an int, such that x = m * 2.**e
_x000D_If x is 0, m and e are both 0. Else 0.5 <= abs(m) < 1.0.
_x000D_fsum(...)
_x000D_fsum(iterable)
_x000D_Return an accurate floating point sum of values in the iterable.
_x000D_Assumes IEEE-754 floating point arithmetic.
_x000D_gamma(...)
_x000D_gamma(x)
_x000D_Gamma function at x.
_x000D_gcd(...)
_x000D_gcd(a, b) -> int
_x000D_greatest common divisor of a and b
_x000D_hypot(...)
_x000D_hypot(x, y)
_x000D_Return the Euclidean distance, sqrt(x*x + y*y).
_x000D_inf = inf
_x000D_isclose(...)
_x000D_isclose(a, b, *, rel_tol=1e-09, abs_tol=0.0) -> bool
_x000D_Determine whether two floating point numbers are close in value.
_x000D_rel_tol
_x000D_maximum difference for being considered "close", relative to the
_x000D_magnitude of the input values
_x000D_abs_tol
_x000D_maximum difference for being considered "close", regardless of the
_x000D_magnitude of the input values
_x000D_Return True if a is close in value to b, and False otherwise.
_x000D_For the values to be considered "close", the difference between them
_x000D_must be smaller than at least one of the tolerances.
_x000D_-inf, inf and NaN behave similarly to the IEEE 754 Standard. That
_x000D_is, NaN is not close to anything, even itself. inf and -inf are
_x000D_only close to themselves.
_x000D_isfinite(...)
_x000D_isfinite(x) -> bool
_x000D_Return True if x is neither an infinity nor a NaN, and False otherwise.
_x000D_isinf(...)
_x000D_isinf(x) -> bool
_x000D_Return True if x is a positive or negative infinity, and False otherwise.
_x000D_isnan(...)
_x000D_isnan(x) -> bool
_x000D_Return True if x is a NaN (not a number), and False otherwise.
_x000D_isqrt(...)
_x000D_isqrt(n: int) -> int
_x000D_Return the integer square root of the nonnegative integer n.
_x000D_This is the largest integer r such that r*r <= n.
_x000D_>>> isqrt(9)
_x000D_3
_x000D_ldexp(...)
_x000D_ldexp(x, i)
_x000D_Return x * (2**i).
_x000D_This is essentially the inverse of frexp().
_x000D_lgamma(...)
_x000D_lgamma(x)
_x000D_Natural logarithm of the absolute value of the Gamma function at x.
_x000D_log(...)
_x000D_log(x, [base=e])
_x000D_Return the logarithm of x to the given base.
_x000D_If the base not specified, returns the natural logarithm (base e) of x.
_x000D_log10(...)
_x000D_log10(x)
_x000D_Return the base 10 logarithm of x.
_x000D_log1p(...)
_x000D_log1p(x)
_x000D_Return the natural logarithm of 1+x (base e).
_x000D_The result is computed in a way which is accurate for x near zero.
_x000D_log2(...)
_x000D_log2(x)
_x000D_Return the base 2 logarithm of x.
_x000D_modf(...)
_x000D_modf(x)
_x000D_Return the fractional and integer parts of x. Both results carry the sign
_x000D_of x and are floats.
_x000D_nan = nan
_x000D_perm(...)
_x000D_perm(N, k=None, exact=False)
_x000D_Number of ways to choose k items from N items with order and without repetition.
_x000D_If k is not specified or is None, then k defaults to N and we compute the number of permutations of N items: N!/(N-N)! = N!.
_x000D_If k is specified, then we compute the number of ways to select k items from N items with order and without repetition: N!/(N-k)!.
_x000D_If exact is true, the result is returned as an integer, otherwise it is returned as a float.
_x000D_pi = 3.141592653589793
_x000D_pow(...)
_x000D_pow(x, y)
_x000D_Return x**y (x to the power of y).
_x000D_prod(...)
_x000D_prod(iterable, *, start=1)
_x000D_Calculate the product of all the elements in the input iterable.
_x000D_The default start value for the product is 1.
_x000D_When the iterable is empty, return the start value. This function is
_x000D_intended specifically for use with numeric values and may reject
_x000D_non-numeric types.
_x000D_radians(...)
_x000D_radians(x)
_x000D_Convert angle x from degrees to radians.
_x000D_remainder(...)
_x000D_remainder(x, y)
_x000D_Return the IEEE 754-style remainder of x with respect to y. For finite x and finite nonzero y, this is the difference x - n*y, where n is the closest integer to the exact value of the quotient x / y. If x / y is exactly halfway between two consecutive integers, the nearest even integer is used for n. The remainder r = remainder(x, y) thus always satisfies abs(r) <= 0.5 * abs(y).
_x000D_sin(...)
_x000D_sin(x)
_x000D_Return the sine of x (measured in radians).
_x000D_sinh(...)
_x000D_sinh(x)
_x000D_Return the hyperbolic sine of x.
_x000D_sqrt(...)
_x000D_sqrt(x)
_x000D_Return the square root of x.
_x000D_tan(...)
_x000D_tan(x)
_x000D_Return the tangent of x (measured in radians).
_x000D_tanh(...)
_x000D_tanh(x)
_x000D_Return the hyperbolic tangent of x.
_x000D_tau = 6.283185307179586
_x000D_trunc(...)
_x000D_trunc(x:Real) -> Integral
_x000D_Truncates x to the nearest Integral toward 0. Uses the __trunc__ magic method.
_x000D_DATA
_x000D_e = 2.718281828459045
_x000D_inf = inf
_x000D_nan = nan
_x000D_pi = 3.141592653589793
_x000D_tau = 6.283185307179586
_x000D_FILE
_x000D_(built-in)
_x000D_(END)
_x000D_ _x000D_从输出结果中，我们可以看到math模块的文档字符串，其中包括模块的名称、描述、函数列表等信息。
_x000D_扩展问答
_x000D_1. 如何查看第三方模块中的方法？
_x000D_答：与查看Python内置模块的方法相同，我们可以使用dir()函数来查看第三方模块中的方法和属性。例如，我们可以使用以下代码来查看第三方模块numpy中的所有方法和属性：
_x000D_ _x000D_import numpy as np
_x000D_print(dir(np))
_x000D_ _x000D_2. 如何查看模块中的指定方法？
_x000D_答：我们可以使用help()函数来查看模块中的指定方法的文档字符串。例如，我们可以使用以下代码来查看Python内置模块math中的acos方法的文档字符串：
_x000D_ _x000D_import math
_x000D_help(math.acos)
_x000D_ _x000D_3. 如何查看模块中的属性？
_x000D_答：我们可以使用dir()函数来查看模块中的属性。例如，我们可以使用以下代码来查看Python内置模块math中的pi属性：
_x000D_ _x000D_import math
_x000D_print(math.pi)
_x000D_ _x000D_4. 如何查看模块中的类？
_x000D_答：我们可以使用dir()函数来查看模块中的类。例如，我们可以使用以下代码来查看Python内置模块datetime中的datetime类：
_x000D_ _x000D_import datetime
_x000D_print(dir(datetime.datetime))
_x000D_ _x000D_本文介绍了如何使用Python的dir()函数来查看模块中的方法和属性，以及使用help()函数来查看模块的文档字符串。还扩展了相关问答，帮助读者更好地了解Python查看模块方法的相关知识。
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