[待总结整理]python笔记

• strip() 移除字符串头尾指定字符
• https://stackoverflow.com/questions/5319922/python-check-if-word-is-in-a-string  找出一个string里是否含有指定字符,可以用find()函数,但返回值是Index if found and -1 otherwise.
  
• 关于判定条件的写法 https://stackoverflow.com/questions/1075652/using-the-and-and-not-operator-in-python
• dictionary 定义,添加新key等
• python的调试方法,似乎pdb可以

$python
>>> import pdb
>>> import myCode
>>> pdb.run(myCode.main())
> (1)()
(Pdb) 

(Pdb) b main
*** The specified object 'main' is not a function
or was not found along sys.path.
(Pdb) b main()
*** The specified object 'main()' is not a function
or was not found along sys.path.
(Pdb) b sortJumpstart.main()
*** The specified object 'sortJumpstart.main()' is not a function
or was not found along sys.path.

以上关于python debug的方法都行不通,而这篇是我目前见过的最好最清晰的一篇关于pdb debug的,而且照学过程中未出现任何问题: https://www.digitalocean.com/community/tutorials/how-to-use-the-python-debugger

这篇我还没细看,不过或许还可以是上一篇的一点补充吧,不过清晰性可能还是不及上一篇

$: python -m pdb test.py arg1

(-m是引入模块的意思,这里引入pdb模块,即调试模块) 

然后一些命令:break, list,continue, next,step,run,help.简写分别为b,l,c,n,s,r,h.打印为p或pp

list可单用,也可加行号,起始行号之间用逗号隔开

设断点的几种方式: 

(1) break test.py:5   (按行号设,当pdb在test处时,可以直接写行号)

(2) break test.nested_loop  (在函数处设)

(3) break test.py:7, number > 500 (加条件)

break单独使用可以显示断点信息,然后用disable和enable开关断点

• 一个貌似不错的python教学网站: https://www.python-course.eu/dictionaries.php   包含Python 2 Tutorial, Python 3 Tutorial, Advanced Topics, Numerical Python, Machine Learning, Tkinter Tutorial等
• print字典 https://stackoverflow.com/questions/15785719/how-to-print-a-dictionary-line-by-line-in-python

for x in cars:
    print (x)
    for y in cars[x]:
        print (y,':',cars[x][y])

• 文件读写https://www.guru99.com/reading-and-writing-files-in-python.html
• https://www.techwalla.com/articles/how-to-convert-int-to-string-in-python
  
• https://www.tutorialspoint.com/python/string_split.htm
  
• https://www.tutorialspoint.com/python/string_strip.htm
  
• https://stackoverflow.com/questions/4642501/how-to-sort-dictionaries-by-keys-in-python
  
• https://stackoverflow.com/questions/379906/parse-string-to-float-or-int
  
• 
  
• 
  
• 参数 https://stackoverflow.com/questions/1009860/how-to-read-process-command-line-arguments

f you need something fast and not very flexible

main.py:

import sys

first_name = sys.argv[1]
last_name = sys.argv[2]
print("Hello " + first_name+ " " + last_name )

Then run python main.py James Smith

to produce the following output:

Hello James Smith

https://www.python-course.eu/python3_print.php

https://stackoverflow.com/questions/15286401/print-multiple-arguments-in-python

https://learnpythonthehardway.org/book/ex5.html

• 排序

https://stackoverflow.com/questions/613183/how-to-sort-a-dictionary-by-value

http://www.jianshu.com/p/0d47cf8577b5

• 集合及各种操作

https://docs.python.org/2/library/sets.html

• 字典的各种操作

https://stackoverflow.com/questions/1602934/check-if-a-given-key-already-exists-in-a-dictionary

https://stackoverflow.com/questions/28859095/most-efficient-method-to-check-if-dictionary-key-exists-and-process-its-value-if

https://stackoverflow.com/questions/3294889/iterating-over-dictionaries-using-for-loops

https://stackoverflow.com/questions/42315072/python-update-a-key-in-dict-if-it-doesnt-exist

• 合并list

http://blog.csdn.net/roytao2/article/details/54180182

list3=list1+list2

• list去重

http://blog.csdn.net/promise_love/article/details/46963589

list2=set(list1)

• 统计重复项

http://blog.csdn.net/duanboqiang/article/details/52945381

from collections import Counter 
Counter(list1) 

• 编码问题

如含中文可加:   #coding=utf-8

http://www.runoob.com/python/python-chinese-encoding.html

https://www.python.org/dev/peps/pep-0263/