Hello Python

《Python 核心编程》

基于python2.7版本

第一章 欢迎来到python世界

1
2
3
#！/usr/bin/env python
# -*- coding: utf-8 -*-
 print 'hello world'

第二章 快速入门

2.1 程序输出
1
print "%s is number %d!" % ("Python", 1), 'what do you think? %.2f' % (2.50)
1
2
import sys
print >> sys.stderr, 'Fatal error: invalid input'
1
2
3
4
# -*- coding: utf-8 -*-
logfile = open('/home/hero/workspace/PythonTest/log', 'a') #a添加、r读、w写
print >> logfile, '可以重定向输出到文件log'
logfile.close()
2.2 程序输入和raw_input()内建函数
1
2
user = raw_input('Enter login name: ')
print 'Your login name is', user
2.4 操作符
算数操作符 方式 示例
+、-、*、/、% 标准操作符
// 浮点除法(四舍五入) 7//2=3
** 乘方操作符 3**2=9
2.18 类
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
#!/usr/bin/env python
# -*- coding: utf-8 -*-
class Foo(object):
    """docstring for Foo"""
    version = 1.0
    """constructor"""
    def __init__(self, nm='John Doe'):
        self.name = nm
        print 'create Foo '+ nm
    def showname(self): #self（java中的this）
        print self.name
    def showver(self):
        print self.version

foo = Foo()
foo.showname()
foo.showver()

foo = Foo('Jimy')
foo.showname()
foo.showver()
2.19 模块

module_cap.py

1
2
3
4
5
6
7
8
9
10
11
# -*- coding:utf-8 -*-
#将每个单词首字母改为大写
def my_cap(s):  # my capitalize fun
    if not isinstance(s, str):
        return
    l = s.split(' ')
    res = ''
    for i in l:
        res += i.capitalize() + ' '
    return res
value=999

test_main.py

1
2
3
4
# -*- coding: utf-8 -*-
from module_cap import *
print my_cap('hello world')
print value

第三章 语句和语法

3.6 文件读写
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
#!/usr/bin/env python
# --*-- coding: utf-8 --*--

"""makeTextFile.py -- create text file"""

import os


def touch_file():
    ls = os.linesep

    # get file name
    while True:
        fname = raw_input('Please enter the file name:("q" to quit) ')
        if fname == 'q':
            return
        elif os.path.exists(fname):
            print "Error: '%s' already exists" % fname
        else:
            break

    # get file content lines
    all = []
    print 'Enter lines ("#" by itself to quit).'

    # loop
    while True:
        entry = raw_input('> ')
        if entry == '#':
            break
        else:
            all.append(entry)

    # write to file
    fobj = open(fname, 'w')
    fobj.writelines(['%s%s' % (x, ls) for x in all])
    fobj.close()
    print 'Done!'

if __name__ == '__main__':
    touch_file()
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
#!/usr/bin/env python
# --*-- coding: utf-8 --*--

"""readTextFile.py -- read text file"""


def read_text_file():
    fname = raw_input('Enter file name: ')
    try:
        fobj = open(fname, 'r')
    except IOError, e:
        print 'file open error:', e
    else:
        for eachLine in fobj:
            print eachLine,
        fobj.close()


if __name__ == '__main__':
    read_text_file()