Tips for writing efficient Python code
2016-10-22 07:59
405 查看
Find the difference of keys between two dictionaries
Suppose two dictionaries A and B. We would like to find the keys in A but not in B.
Bad example:
import time
A = {}
B = {}
for i in range(1000):
A[i] = i
for i in range(800, 1800):
B[i] = i
result = []
t = time.clock()
for key in A:
if (B.has_key(key) != True):
result.append(key)
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result) elapsed time :1.58506018256e-06
import time
A = {}
B = {}
for i in range(1000):
A[i] = i
for i in range(800, 1800):
B[i] = i
result = []
t = time.clock()
for key in A:
if (key not in B):
result.append(key)
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :1.06822538939e-06
Good example:
import time
A = {}
B = {}
for i in range(1000):
A[i] = i
for i in range(800, 1800):
B[i] = i
result = []
t = time.clock()
result = list(set(A) - set(B))
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :4.65752280715e-07
Sort and Iterate the Dictionary
Here we use the OrderedDict to sort normal dictionary
Bad example:
import time
import collections
A = {}
for i in range(1000):
A[i] = i
A = collections.OrderedDict(sorted(A.items()))
#A = dict(A)
t = time.clock()
result = 0
for key in A:
result += 1
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :9.57045813266e-07
Good example:
import time
import collections
A = {}
for i in range(1000):
A[i] = i
A = collections.OrderedDict(sorted(A.items()))
A = dict(A)
t = time.clock()
result = 0
for key in A:
result += 1
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :4.95800812545e-07
Suppose two dictionaries A and B. We would like to find the keys in A but not in B.
Bad example:
import time
A = {}
B = {}
for i in range(1000):
A[i] = i
for i in range(800, 1800):
B[i] = i
result = []
t = time.clock()
for key in A:
if (B.has_key(key) != True):
result.append(key)
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result) elapsed time :1.58506018256e-06
import time
A = {}
B = {}
for i in range(1000):
A[i] = i
for i in range(800, 1800):
B[i] = i
result = []
t = time.clock()
for key in A:
if (key not in B):
result.append(key)
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :1.06822538939e-06
Good example:
import time
A = {}
B = {}
for i in range(1000):
A[i] = i
for i in range(800, 1800):
B[i] = i
result = []
t = time.clock()
result = list(set(A) - set(B))
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :4.65752280715e-07
Sort and Iterate the Dictionary
Here we use the OrderedDict to sort normal dictionary
Bad example:
import time
import collections
A = {}
for i in range(1000):
A[i] = i
A = collections.OrderedDict(sorted(A.items()))
#A = dict(A)
t = time.clock()
result = 0
for key in A:
result += 1
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :9.57045813266e-07
Good example:
import time
import collections
A = {}
for i in range(1000):
A[i] = i
A = collections.OrderedDict(sorted(A.items()))
A = dict(A)
t = time.clock()
result = 0
for key in A:
result += 1
elapsed_time = time.clock() - t
print ('elapsed time :' + str(elapsed_time/num_product))
print (result)
elapsed time :4.95800812545e-07
相关文章推荐
- Writing Efficient C Code for Embedded Systems
- 10 Tips for Writing Better Code (阅读理解)
- Thread safe tips for python extending
- 40 Tips for optimizing your php Code
- 10 Tips for Writing High-Performance Web Applications
- Style Guide for Python Code
- 笔记--- Writing Code for ROM
- 《Writing Clear Code---- Microsoft Techniques for Developing Bug-free C Programs 》摘录
- Writing Efficient C and C Code Optimization
- 10 Tips for Writing High-Performance Web Applications
- Tips for Writing a File System Filter
- 10 Tips for Writing High-Performance Web Applications
- Good tips for being efficient
- 10 Tips for Writing Better MRDs - Part 1
- Tips for writing ASP.NET composite controls
- CodeWarrior for Freescale S12 开发Tips
- Style Guide for Python Code 推荐的python代码风格
- Writing Efficient Android Code(转)
- 标签 -- Some Cool Tips for .NET (From CodeProject)
- Writing Efficient CSS for use in the Mozilla UI