Python Tips & Tricks

读写

for line in opened_file: 逐行读取，读一行加载一行
for line in opened_file.readlines(): 逐行读取，将所有内容加载到内存
for row in cursor: 逐row读取，读一行加载一行
for row in cursor.fetchall() : 逐row读取，将所有内容加载到内存

注意: 单次循环中，计算任务所花的时间 >> 单次IO读取的时间时， for line in file/cursor 更好单次循环中，计算任务所花的时间 << 单次IO读取的时间时， for line in file.readlines()/cursor.fetchall() 更好

Statistics

Seaborn

画分布图

http://seaborn.pydata.org/examples/distplot_options.html?highlight=distribution



In [16]:

    
%matplotlib inline

import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

rs = np.random.RandomState(10)
# Plot a historgram and kernel density estimate
sns.distplot(rs.normal(size=100), color="m")









    



/Users/marc/anaconda/lib/python3.5/site-packages/statsmodels/nonparametric/kdetools.py:20: VisibleDeprecationWarning: using a non-integer number instead of an integer will result in an error in the future
  y = X[:m/2+1] + np.r_[0,X[m/2+1:],0]*1j






    Out[16]:





<matplotlib.axes._subplots.AxesSubplot at 0x11be6d860>



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