lower()|upper()|Traceback|title()|字符串合并|rstrip|lstrip|str()|

 print ("hello,world!")
 sentence = "yyyy"
 print (sentence.lower())
 print (sentence.upper())

 #print (sentenc)

 #hello,world!
 #yyyy
 #YYYY
 #Traceback (most recent call last):
 #      File "t.py", line 4, in <module>
 #          print (sentenc)
 #          NameError: name 'sentenc' is not defined

 print ('his name is "Li"')

 #his name is "Li"

 first = "a    "
 first_1 ="a"
 if first == first_1:
     print ("fit!")
 else:
     print ("wrong!")

 second = "b"
 print "\took"+first.rstrip() + "      " +second.title()+"!"

 #wrong!
 #        ooka          B!

 p = (2+3)**3
 Q = 0.1 *3
 print str(p)+""+str(Q)

 #1250.3