python学习笔记

python是完全面向对象语言

字符串

自然字符串： 如果你想要指示某些不需要如转义符那样的特别处理的字符串，那么你需要指定一个自然字符串。自然字符串通过给字符串加上前缀r或R来指定。例如r"Newlines are indicated by \n"。 

# FILENAME : 2.pyi = 5print ii=i+1;print i;s='''this is a multi-line string.this is the second line.'''print sq='''this is a multi-line string.\this is the second line.'''print q

输出：

jiao.geng@jiaogeng-Latitude-E5450:~/python$ python 2.py 56this is a multi-line string.this is the second line.this is a multi-line string.this is the second line.

使用if语句

 #!/usr/bin/python# Filename: if.pynumber = 23guess = int(raw_input('Enter an integer : '))if guess == number:    print 'Congratulations, you guessed it.' # New block starts here    print "(but you do not win any prizes!)" # New block ends hereelif guess < number:    print 'No, it is a little higher than that' # Another block    # You can do whatever you want in a block ...else:    print 'No, it is a little lower than that'    # you must have guess > number to reach hereprint 'Done'# This last statement is always executed, after the if statement is executed 

输出：

$ python if.py
Enter an integer : 50
No, it is a little lower than that
Done
$ python if.py
Enter an integer : 22
No, it is a little higher than that
Done
$ python if.py
Enter an integer : 23
Congratulations, you guessed it.
(but you do not win any prizes!)
Done