Pyhton で、数値のオーダーを取得するコードを書いてみました。例えば、数値が 123 なら、2 を得ます。あまり自信はありません。
%reset -f
import sys
#from sympy import *
import sympy
def getOrderOfMagnitude(tmpStr):
orderOfMagnitude = None
sign = None
#typeArray = ["<class 'sympy.core.numbers.Integer'>", "<class 'sympy.core.numbers.Float'>", "<class 'sympy.core.numbers.Zero'>", "<class 'sympy.core.numbers.One'>"]
typeArray = ["<class 'sympy.core.numbers.Integer'>", "<class 'sympy.core.numbers.Float'>", "<class 'sympy.core.numbers.Zero'>", "<class 'sympy.core.numbers.One'>", "<class 'sympy.core.numbers.NegativeOne'>"]
try:
expr = sympy.sympify(tmpStr, evaluate=True)
except Exception as ex:
expr = ex
print('expr : ', expr)
exprClass = str(type(expr))
if exprClass == "<class 'sympy.core.sympify.SympifyError'>":
return sign, orderOfMagnitude, "is not numerical value or expression."
# 以下、とりあえず数式にはなっている
# ゼロは対数計算ができない
if exprClass == "<class 'sympy.core.numbers.Zero'>":
sign = 0
return sign, orderOfMagnitude, "is Zero."
if exprClass in typeArray:
if expr > 0:
sign = +1
else:
sign = -1
orderOfMagnitude = int(float(sympy.log(sympy.Abs(expr), 10)))
return sign, orderOfMagnitude, "float or integer"
else:
return sign, orderOfMagnitude, "is expression. But is not numerical value."
testArray = []
testArray.append('0')
testArray.append('1')
testArray.append('-1')
testArray.append('2')
testArray.append('100')
testArray.append('123')
testArray.append('0.010')
testArray.append('0.012')
testArray.append('0.00123')
testArray.append('-123')
testArray.append('- 123') # 符号との間に空白
testArray.append('-123 ') # 右側に空白
testArray.append(' - 123 ') # 多数の空白
testArray.append(' -0123 ')
testArray.append('-0.123')
testArray.append('0.12e-3')
testArray.append('-0.12e-3')
testArray.append('-0.12E-3')
testArray.append('-0.0120e-3')
testArray.append(' + 0.01200e-3')
testArray.append('-2.14*10^3')
testArray.append('-2.14*10**3')
testArray.append('123*10^2*3*10^2')
testArray.append('x*y')
testArray.append('sin(x)')
testArray.append('x[0]')
testArray.append('x1')
testArray.append('2*pi')
for i in range(len(testArray)):
tmpStr = testArray[i]
significantFigures = -1
orderOfMagnitude = None
sign = None
print('\nNo. ' + str(i))
print('"' + tmpStr + '"')
sign, orderOfMagnitude, message = getOrderOfMagnitude(tmpStr)
print(message)
print('sign : ' + str(sign) + ', orderOfMagnitude : ' + str(orderOfMagnitude))
getOrderOfMagnitude という関数に数式を文字列で渡すと、符号とオーダーと数値なのかどうかなどの情報の３変数を返します。以下が実行結果です。
No. 0
"0"
expr : 0
is Zero.
sign : 0, orderOfMagnitude : None
No. 1
"1"
expr : 1
float or integer
sign : 1, orderOfMagnitude : 0
No. 2
"-1"
expr : -1
float or integer
sign : -1, orderOfMagnitude : 0
No. 3
"2"
expr : 2
float or integer
sign : 1, orderOfMagnitude : 0
No. 4
"100"
expr : 100
float or integer
sign : 1, orderOfMagnitude : 2
No. 5
"123"
expr : 123
float or integer
sign : 1, orderOfMagnitude : 2
No. 6
"0.010"
expr : 0.0100000000000000
float or integer
sign : 1, orderOfMagnitude : -2
No. 7
"0.012"
expr : 0.0120000000000000
float or integer
sign : 1, orderOfMagnitude : -1
No. 8
"0.00123"
expr : 0.00123000000000000
float or integer
sign : 1, orderOfMagnitude : -2
No. 9
"-123"
expr : -123
float or integer
sign : -1, orderOfMagnitude : 2
No. 10
"- 123"
expr : -123
float or integer
sign : -1, orderOfMagnitude : 2
No. 11
"-123 "
expr : -123
float or integer
sign : -1, orderOfMagnitude : 2
No. 12
" - 123 "
expr : -123
float or integer
sign : -1, orderOfMagnitude : 2
No. 13
" -0123 "
expr : Sympify of expression 'could not parse ' -0123 '' failed, because of exception being raised:
SyntaxError: invalid syntax (<string>, line 1)
is not numerical value or expression.
sign : None, orderOfMagnitude : None
No. 14
"-0.123"
expr : -0.123000000000000
float or integer
sign : -1, orderOfMagnitude : 0
No. 15
"0.12e-3"
expr : 0.000120000000000000
float or integer
sign : 1, orderOfMagnitude : -3
No. 16
"-0.12e-3"
expr : -0.000120000000000000
float or integer
sign : -1, orderOfMagnitude : -3
No. 17
"-0.12E-3"
expr : -0.000120000000000000
float or integer
sign : -1, orderOfMagnitude : -3
No. 18
"-0.0120e-3"
expr : -1.20000000000000e-5
float or integer
sign : -1, orderOfMagnitude : -4
No. 19
" + 0.01200e-3"
expr : 1.20000000000000e-5
float or integer
sign : 1, orderOfMagnitude : -4
No. 20
"-2.14*10^3"
expr : -2140.00000000000
float or integer
sign : -1, orderOfMagnitude : 3
No. 21
"-2.14*10**3"
expr : -2140.00000000000
float or integer
sign : -1, orderOfMagnitude : 3
No. 22
"123*10^2*3*10^2"
expr : 3690000
float or integer
sign : 1, orderOfMagnitude : 6
No. 23
"x*y"
expr : x*y
is expression. But is not numerical value.
sign : None, orderOfMagnitude : None
No. 24
"sin(x)"
expr : sin(x)
is expression. But is not numerical value.
sign : None, orderOfMagnitude : None
No. 25
"x[0]"
expr : 'Symbol' object is not subscriptable
is expression. But is not numerical value.
sign : None, orderOfMagnitude : None
No. 26
"x1"
expr : x1
is expression. But is not numerical value.
sign : None, orderOfMagnitude : None
No. 27
"2*pi"
expr : 2*pi
is expression. But is not numerical value.
sign : None, orderOfMagnitude : None