Python

about_random.py

import random
# 生成5个0~9的不重复随机数
print random.sample(range(10), 5)
# [7, 9, 6, 2, 3]

# 从a~d中取出不重复的三个字母
print random.sample(['a', 'b', 'c', 'd'], 3)
# ['d', 'b', 'c']

dict_operation.py

# http://stackoverflow.com/a/8381589/4003204

### Making a dictionary ###

data = {}
# OR
data = dict()

### Initially adding values ###

data = {'a':1,'b':2,'c':3}
# OR
data = dict(a=1, b=2, c=3)

### Inserting/Updating value ###

data['a']=1  # updates if 'a' exists, else adds 'a'
# OR
data.update({'a':1})
# OR
data.update(dict(a=1))
# OR
data.update(a=1)

### Merging 2 dictionaries ###

data.update(data2)  # Where data2 is also a dict.

### Deleting items in dictionary ###

del data[key] #Remove specific element in a dictionary
data.pop(key) #Removes the key & returns the value
data.clear() #Clear entire dictionary