python练习小例子（一）
1、if语句
1 #!/user/local/bin/python
2 a = 1
3 b = 2
4 if a < b:
5 pass
6 else:
7 print a
8 print "-----"
9
10 a = '+'
11 if a == '+':
12 print "+"
13 elif a == '-':
14 print "-"
15 print "-----"
16
17 a = 1
18 b = 2
19 c = 3
20 if b >= a and b <= c:
21 print "b is between a and c"
22 if not ( b < a or b > c):
23 print "b is still between a and c"
2、file文件操作
1 #!/user/local/bin/python
2 f = open("f.txt")
3 line = f.readline()
4 while line:
5 print line,
6 line = f.readline()
7 f.close()
8
9 f = open("f.txt","a+")
10 i = 0
11 k = 1.1313
12 #while i < 10:
13 # print >> f, "%d %0.2f" % (i, k)
14 # i += 1
15 f.writelines("111111")
16 f.close()
17 l = "asd" + "sad" + "asd"
18 print l
3、string操作
1 #!/user/loacl/bin/python
2 a = 'hello world'
3 b = "asdads"
4 c = """asdasda"""
5 print a
6 print b
7 print c
8 d = "0123456789"
9 f= d[1:4]
10 print f
11 f= d[:6]
12 print f
13 f= d[2:]
14 print f
15
16 a=1
17 b="222"
18
19
20 b = b + str(a)
21 print b
22
23 b = b + repr(a)
24 print b
25
26 b = b + 'y'
27 print b
28
29 s = raw_input(" sadasdsa: ")
30 print "%s" % (s,)
4、list操作
1 #!/user/loacl/bin/python
2 names = [ "12", "34", "45", "56"]
3 print names[1]
4 print len(names)
5 names.append("78")
6 names.insert(2,"www")
7 print names[0:2]
8 print names[2:]
9 names[0:2] = [ "qq" , "qqq", "qqqq"]
10 print names[1]
11 a = [1, 2, 3] + [4,5]
12 print a
13 a = [ 1, 2, 3.23, ["mas", 7, 9,[100, 22], 10]]
14 print a[1]
15 print a[3][2]
16 print a[3][3][1]
17 print "=------"
18 b = [1, 2 , 3]
19 b.insert(2,"wwww")
20 print b
21
22 print "1111111111111111111"
