python版本
雖然python3已經(jīng)發(fā)布很長時間了姚垃,但現(xiàn)在大部分開發(fā)者使用的版本還是python2淑倾。主要原因是python3的改動比較大,并且向下兼容性不是很好休玩,但是python3是未來的發(fā)展方向狂鞋,所以作為初學(xué)者還是推薦學(xué)習(xí)python3版本片择。
[centos@bogon ~]$ python
Python 2.6.6 (r266:84292, Nov 22 2013, 12:16:22)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>>
>>>
>>>
[centos@bogon ~]$ python3
Python 3.4.4 (default, Jan 5 2016, 21:54:11)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
python的安裝
下面主要介紹在python2的基礎(chǔ)上安裝python3(python2與python3版本共存),因為現(xiàn)在大部分linux發(fā)現(xiàn)版本自帶的python版本還是python2
- 安裝環(huán)境
yum install gcc
yum install zlib-devel
yum install make
- 下載python3版本
進(jìn)入網(wǎng)站選擇python版本:https://www.python.org/ftp/python/
這里選擇的是Python-3.4.4.tgz
wget http://www.python.org/ftp/python/3.4.4/Python-3.4.4.tgz
- 解壓骚揍、編輯和安裝
tar -zxvf Python-3.4.0.tgz
cd Python-3.4.0
./configure –prefix=/opt/python3
make all
make install
- 鏈接到bin目錄
ln -s /opt/python3/bin/python3 /usr/bin/python3
提示:在python交互模式下方向鍵變字母的問題
#安裝readline-devel
$yum install readline-devl
#重新安裝python
$./configure
$sudo make install
字符串
三種引號的區(qū)別
實例:
>>> 'hello python3'
'hello python3'
>>>
>>> "this's python3"
"this's python3"
>>>
>>>
>>> """hello python3
... this's python3"""
"hello python3\nthis's python3"
提示:具體使用哪種方式根據(jù)需求靈活選擇
字符串連接
實例:
>>> "michael"+" "+"jackson"
'michael jackson'
>>>
>>> "micheal" "jackson"
'michealjackson'
>>>
>>> "micheal " "jackson"
'micheal jackson'
注意:不推薦使用第二種方式
格式說明符
實例:
>>> "John %s%s" % ("Every", "Man")
'John EveryMan'
>>>
>>> "%s %s %10s" % ("John" , "Every" , "Man")
'John Every Man'
>>>
>>> "%-8s %s %10s" % ("John" , "Every" , "Man")
'John Every Man'
原始字符串與Unicode
原始字符串r:
>>> print('Hello.\npython!')
Hello.
python!
>>>
>>> print(r'Hello.\npython!')
Hello.\npython!
Unicode對象:
python中的普通字符串在內(nèi)部是以8位的ASCII碼形式存儲的字管,而Unicode字符串則存儲為16的Unicode字符啰挪,這樣能夠表示更多的字符集。
>>> u'Hello.world!'
'Hello.world!'
>>>
數(shù)值與運算符
三種數(shù)值類型
>>> type(1)
<class 'int'>
>>>
>>> type(1.0)
<class 'float'>
>>>
>>> type(1j)
<class 'complex'>
簡單數(shù)值運算
>>> 1+1
2
>>>
>>> 1+1.0
2.0
>>>
>>> 2e23445*3e45464
inf
>>>
>>> 33/11
3.0
>>>
>>> 4.0/2.0
2.0
>>>
>>> 5/3
1.6666666666666667
>>>
>>> 5%3
2
數(shù)值格式化
>>> print("%.2f" % 2.322551)
2.32
>>>
>>> print("%0.f" % (343*0.2))
69
參考
《Python編程入門經(jīng)典》