python 快速入门

导入

#from dir1 import test

#import dir1.test as test

列表推到：

b3 =[x for x in xing if x in ming]
print(b3)

 li = [1, 2, 3, 4]
[elem*2 for elem in li] 

print [x*y for x in [1,2,3] for y in  [1,2,3]]

zip:

l1=[1,2,3,4]
l2=[2,4,6,7]
print(zip(l1,l2))
for (a,b)in zip(l1,l2):
    print((a,b))

enumerate:

testStr = 'cainiao'
for (offset,item) in enumerate(testStr):
  print (item,'appears at offset:',offset)

has_key was removed from python3.x and use （key in dict)

http://blog.csdn.net/dingyaguang117/article/details/7170881

http://www.cainiao8.com/python/basic/python_11_for.html

循环组合

while i<len(xing):
    print ([xing[i]+ming[i]])
    i=i+1

xing=['wang','li','zhang',"liu"]
for i in range(len(xing)):
     print (i, xing[i])

for i in range(1, 5):
    print i
else:
    print 'The for loop is over'

while True:
    s = raw_input('Enter something : ')
    if s == 'quit':
        break
    if len(s) < 3:
        continue
    print 'Input is of sufficient length'

快速生成词典

---------

list1 =['a','b','c','d']
d = {}
list2=[24, 53, 26, 9]
i=0
while i <len(list1) :
    d[list1[i]]=list2[i]
    i=i+1
print(d)

list1 =['a','b','c','d']
d = {'a':24, 'b':53 ,'c':26, 'd':9}
new_list = [d[k] for k in list1]
assert new_list == [24, 53, 26, 9]

定位字符的位置

------------------

def read_line(line):
    sample = {}
    n = len(line)
    for i in range(n):
      if line[i]!='0':
        sample[i] = int(line[i])
        '''sample[i] is key  int(line[i]) means make it int type'''
        print(sample)
    return sample
  
print(read_line('01101001'))

字符个数统计

d={}
x_string='Pythonhello'
for x in x_string:
    key=x.rstrip()
    if key in d:
        d[key]=d[key]+1
    else:
        d[key] = 1

for k,v in d.items():
    print("%s=%s"%(k,v))

http://www.cainiao8.com/python/basic/python_07_dictionary_tuple.html

------------------------------------

导入

'''import hello
name_pr(q,b,c)
a=hello.name_pr(2,3,4)
print(a)''

引用计算单词数目

1. import sys  

2. import string  

3. #import collections  

4.   

5. if len(sys.argv) == 1 or sys.argv[1] in {"-h", "--help"}:  

6.  print("usage: uniqueword filename_1 filename_2 ... filename_n")  

7.  sys.exit()  

8. else:  

9.  words = {}   

10.  # words = collections.defaultdict(int)  

11.  strip = string.whitespace + string.punctuation + string.digits + "\"'"  

12.  for filename in sys.argv[1:]:  

13.   for line in open(filename):  

14.    for word in line.split():  

15.     word = word.strip(strip)  

16.     if len(word) >= 2:  

17.      words[word] = words.get(word, 0) + 1  

18.      # words[word] += 1  

19.  for word in sorted(words):  

20.   print("'{0}' occurs {1} times".format(word,words[word])) 
    可以使用get()方法来访问字典项,get()方法还可以设置第二个参数，如果b不存在，可以将第二个参数做为默认值返回。

高级函数

http://www.cainiao8.com/python/basic/python_13_function_adv.html

迭代器

#iterator
testDict = {'name':'Chen  Zhe','gender':'male'}
testIter = iter(testDict)
print testIter.next()

异常处理

http://www.cainiao8.com/python/basic/python_16_exception.html

字典(dict)转为字符串(string)

for key, value in sample_dic.items():
    print "\"%s\":\"%s\"" % (key, value)

字符串(string)转为字典(dict)

>>> a = "{'a': 'hi', 'b': 'there'}"
>>> b = eval(a)
>>> b
{'a': 'hi', 'b': 'there'}
>>> exec ("c=" + a)
>>> c
{'a': 'hi', 'b': 'there'}
>>> 

http://www.pythonclub.org/python-hacks/start