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Python運(yùn)算符詳解—— **和*的區(qū)別說(shuō)明

一級(jí)內(nèi)心戲表演藝術(shù)家 2021-08-12 10:22:30 瀏覽數(shù) (5442)
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在數(shù)學(xué)中我們知道一個(gè)數(shù)連續(xù)乘另一個(gè)數(shù),這種操作叫做乘方,乘方的運(yùn)算結(jié)果叫冪,所以乘方運(yùn)算也可以叫求冪,那么python乘方運(yùn)算是怎么表達(dá)的呢?今天小編就帶來(lái)一篇python運(yùn)算符詳解,希望能給各位小伙伴帶來(lái)一點(diǎn)幫助。

我們知道**代表次方。

如下

>>>12 * 12
144
>>>12 ** 2
144


>>>a=1e200
>>> a
1e+200
>>>a ** 2
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OverflowError: (34, 'Result too large')
>>>a * a
inf
>>>a = 100 ** 100  # python3中int整型一般不會(huì)溢出,取決于內(nèi)存
100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>>>a * a,a ** 2   # 兩種方式都沒(méi)問(wèn)題,int很大,不會(huì)溢出,取決于內(nèi)存
(10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000, 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000)
>>>float(a) * float(a)    #float用這種方法,也不會(huì)溢出
inf
>>>float(a) ** 2  #float用這種方式有可能溢出,注意?。?!
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OverflowError: (34, 'Result too large')

補(bǔ)充:python3.8中運(yùn)算符/和//區(qū)別

看下面這兩張圖:

運(yùn)算結(jié)果

運(yùn)算結(jié)果

5/5的結(jié)果為1.0,5//5的結(jié)果為1

6.0/5.0的結(jié)果為1.2,6.0//5.0的結(jié)果為1.0

由此可見(jiàn),使用/運(yùn)算符時(shí),即使兩參數(shù)都是int,返回值都是float,而運(yùn)算符//只有當(dāng)參數(shù)中含有float時(shí),返回值是float,但是結(jié)果是取整的。

/和//的主要區(qū)別:

//運(yùn)算符的結(jié)果是最小取整的,/運(yùn)算符會(huì)保留小數(shù)位

補(bǔ)充:python3中運(yùn)算符及其優(yōu)先級(jí)

1. 一般運(yùn)算符:

+ - * /(真除法) % //(地板除-floor) **(冪運(yùn)算)

2. 賦值運(yùn)算符:

=

3. 增強(qiáng)運(yùn)算符(增強(qiáng)賦值運(yùn)算符)

+= -= *= /= %= **= //=

a+=1 (運(yùn)行效率高)

a=a+1 (運(yùn)行效率低)

4. 布爾運(yùn)算符(比較運(yùn)算符)

== > < >= <= !=

可以連續(xù)判斷:

3>2>1

True

3>2 and 2>1

True

5. 邏輯運(yùn)算符

not and or 優(yōu)先級(jí):

not優(yōu)先級(jí)最高

and

or 優(yōu)先級(jí)最低

6. 位運(yùn)算符

位:二進(jìn)制下的每一個(gè)位

<< >> :移位運(yùn)算符

&:邏輯求與

|:邏輯求或

~:邏輯求非

^:邏輯求異或

7. 三元運(yùn)算符

變量=(值1 if 布爾表達(dá)式 else 值2)

如果布爾表達(dá)式位真則返回值1否則返回值2

運(yùn)算符中,三元運(yùn)算符的優(yōu)先級(jí)最低

1. 先乘除后加減

2. 冪運(yùn)算優(yōu)先級(jí)最高

3. 三元運(yùn)算符優(yōu)先級(jí)最低

4. 元數(shù)越少,優(yōu)先級(jí)越高

冪運(yùn)算:一元運(yùn)算符

5. 優(yōu)先級(jí)從高到低排列:

冪運(yùn)算

正負(fù)號(hào)

算數(shù)運(yùn)算符(— = * /)

比較運(yùn)算符(< > <= >=)

邏輯運(yùn)算符(not and or)

以上就是python運(yùn)算符詳解的全部?jī)?nèi)容,希望能給大家一個(gè)參考,也希望大家多多支持W3Cschool


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