プログラミング学習の記録 574.3 『初めてのコンピュータサイエンス』(Jennifer Campbell, Paul Gries, Jason Montojo, Greg Wilson 著、長尾 高弘 訳、オライリー・ジャパン、2010年、ISBN978-4-87311-463-7)の4章(モジュール)の練習問題1

開発環境

• Mac OS X Snow Leopard (OS)
• WingIDE
• Script言語: Python

『初めてのコンピュータサイエンス』(Jennifer Campbell, Paul Gries, Jason Montojo, Greg Wilson 著、長尾 高弘 訳、オライリー・ジャパン、2010年、ISBN978-4-87311-463-7)の4章(モジュール), 4.8(練習問題)1(a, b)を解いてみる。

 

1(a, b).

入出力結果(Python Shell)

Python 2.6.6 (r266:84374, Aug 31 2010, 11:00:51) [GCC 4.0.1 (Apple Inc. build 5493)] Type "help", "copyright", "credits" or "license" for more information. >>> import math >>> help (math) Help on module math: NAME math FILE /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-dynload/math.so MODULE DOCS http://docs.python.org/library/math DESCRIPTION This module is always available. It provides access to the mathematical functions defined by the C standard. FUNCTIONS acos(...) acos(x) Return the arc cosine (measured in radians) of x. acosh(...) acosh(x) Return the hyperbolic arc cosine (measured in radians) of x. asin(...) asin(x) Return the arc sine (measured in radians) of x. asinh(...) asinh(x) Return the hyperbolic arc sine (measured in radians) of x. atan(...) atan(x) Return the arc tangent (measured in radians) of x. atan2(...) atan2(y, x) Return the arc tangent (measured in radians) of y/x. Unlike atan(y/x), the signs of both x and y are considered. atanh(...) atanh(x) Return the hyperbolic arc tangent (measured in radians) of x. ceil(...) ceil(x) Return the ceiling of x as a float. This is the smallest integral value >= x. copysign(...) copysign(x, y) Return x with the sign of y. cos(...) cos(x) Return the cosine of x (measured in radians). cosh(...) cosh(x) Return the hyperbolic cosine of x. degrees(...) degrees(x) Convert angle x from radians to degrees. exp(...) exp(x) Return e raised to the power of x. fabs(...) fabs(x) Return the absolute value of the float x. factorial(...) factorial(x) -> Integral Find x!. Raise a ValueError if x is negative or non-integral. floor(...) floor(x) Return the floor of x as a float. This is the largest integral value <= x. fmod(...) fmod(x, y) Return fmod(x, y), according to platform C. x % y may differ. frexp(...) frexp(x) Return the mantissa and exponent of x, as pair (m, e). m is a float and e is an int, such that x = m * 2.**e. If x is 0, m and e are both 0. Else 0.5 <= abs(m) < 1.0. fsum(...) fsum(iterable) Return an accurate floating point sum of values in the iterable. Assumes IEEE-754 floating point arithmetic. hypot(...) hypot(x, y) Return the Euclidean distance, sqrt(x*x + y*y). isinf(...) isinf(x) -> bool Check if float x is infinite (positive or negative). isnan(...) isnan(x) -> bool Check if float x is not a number (NaN). ldexp(...) ldexp(x, i) Return x * (2**i). log(...) log(x[, base]) Return the logarithm of x to the given base. If the base not specified, returns the natural logarithm (base e) of x. log10(...) log10(x) Return the base 10 logarithm of x. log1p(...) log1p(x) Return the natural logarithm of 1+x (base e). The result is computed in a way which is accurate for x near zero. modf(...) modf(x) Return the fractional and integer parts of x. Both results carry the sign of x and are floats. pow(...) pow(x, y) Return x**y (x to the power of y). radians(...) radians(x) Convert angle x from degrees to radians. sin(...) sin(x) Return the sine of x (measured in radians). sinh(...) sinh(x) Return the hyperbolic sine of x. sqrt(...) sqrt(x) Return the square root of x. tan(...) tan(x) Return the tangent of x (measured in radians). tanh(...) tanh(x) Return the hyperbolic tangent of x. trunc(...) trunc(x:Real) -> Integral Truncates x to the nearest Integral toward 0. Uses the __trunc__ magic method. DATA e = 2.7182818284590451 pi = 3.1415926535897931 >>> math.fabs(round(-4.3)) Traceback (most recent call last): File "<string>", line 1, in <fragment> IndentationError: unexpected indent (<wingdb_compile>, line 1) >>> math.fabs(round(-4.3)) 4.0 >>> math.ceil(math.tan(34.5)) -0.0 >>> math.ceil(math.sin(34.5)) 1.0 >>> abs(round(-4.3)) 4.0 >>>

helpを参照しても四捨五入する関数が見つからなかったのでなんとなくroundを使ってみたら上手くいった。

もしやと思ってmathモジュールのfabs()関数のかわりにabs()関数でも上手くいくかもと思って最後に試してみたら上手くいった。

ということは、aの四捨五入して絶対値を求めるためだけならmathモジュールをインポートしなくてもいいのかも？

あと、気をつけることとして最初にスペースを挿入すると上手くいかない！(それで最初に-4.3を四捨五入して絶対値を求めようとしたとき失敗したみたい。)