python之數值型別

數值型別分為int型別和float型別#和其他程式語言一樣

python中+，-，*，/的使用同其他程式語言也一樣，遵循先乘除後加減，括號內先執行，略微不同的是/,稍後有介紹

>>> 2 + 2
4>>> 50 - 5*6
20>>> (50 - 5*6) / 4
5.0//the operators +, -, * and / work just like in most other languages (for example, pascal or c);

>>> 17 / 3  # classic division returns a float
5.666666666666667
//此處『/』預設返回的是浮點數型別（相比c語言中的'/'，都是整數預設返回整數，類似求整操作，而python中返回float，取整操作為『//』）
>>>
>>> 17 // 3  # floor division discards the fractional part
5//python中的取整操作
>>> 17 % 3  # the % operator returns the remainder of the division
2 //返回餘數
>>> 5 * 3 + 2  # result * divisor + remainder
17

#x**y等於power（x,y）
>>> 5 ** 2  # 5 squared
25//5的平方
>>> 2 ** 7  # 2 to the power of 7
128//2的7次方

>>> width = 20
>>>width
20>>> height = 5 * 9
>>>height
45>>> width * height
900//『=』等號用以給變數賦值

>>> n  # try to access an undefined variable
traceback (most recent call last):
file "", line 1, in nameerror: name 'n' is not defined
//如果沒有事前定義變數，直接使用會出錯

>>> tax = 12.5 / 100
>>> price = 100.50
>>> price * tax
12.5625
>>> price + _
113.0625
//此處_值為上一步price * tax的值12.5625
>>> round(_, 2)
113.06
//此處_值為上一步列印出來的113.0625，操作保留2位小數

t = true
f = false
print(type(t)) # prints ""
print(t and f) # logical and; prints "false"
print(t or f) # logical or; prints "true"
print(not t) # logical not; prints "false"
print(t != f) # logical xor; prints "true"

hello = 'hello' # string literals can use single quotes
world = "world" # or double quotes; it does not matter.
print(hello) # prints "hello"
print(len(hello)) # string length; prints "5"
hw = hello + ' ' + world # string concatenation
print(hw) # prints "hello world"
hw12 = '%s %s %d' % (hello, world, 12) # sprintf style string formatting
print(hw12) # prints "hello world 12"

s = "hello"
print(s.capitalize()) # capitalize a string; prints "hello"
print(s.upper()) # convert a string to uppercase; prints "hello"
print(s.rjust(7)) # right-justify a string, padding with spaces;
print(s.center(7)) # center a string, padding with spaces; 
print(s.replace('l', '(ell)')) 
# replace all instances of one substring with another substring
# prints "he(ell)(ell)o"
print(' world '.strip()) # strip leading and trailing whitespace;

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python之數值型別

Python 數值型別

Python 數值型別

Python 數值型別

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