Some useful Coding techniques

Table of content

#Git

###Remove bad commit from remote

• Move head to the good commit git reset --hard <good commit id>
• Force push the good commit to git git push origin HEAD --force

###Revert to some previous commit

• Check all previous commits by git log

• Pick up a commit by commit code, e.g.,

  commit 955cd428160a6d61a260564b193b175ae26f43c2

• As a alternative, you can check the commit with commit id in GitHub webpage or client.

• Revert to the selected commit

git checkout 955cd428160a6d61a260564b193b175ae26f43c2

###Remove files from Git but keep local copies

• Check files that are tracked by Git

git ls-files

• Remove files from Git tracking system

git rm --cached filename

• Check the revision of the repository

git status

• Modify the tracked file list

git add -u

• Commit changes

git commit -m'commit message'

#Python

###Repeat a string

'this is a string' * 100

###Sort a list nums and return index

>>> nums=[1,2,3,4,2,2,1,2,3,2,1,2,3,4,5]
>>> ind = sorted(range(len(nums)), key = lambda x: nums[x])

###Iterate over a list with index and value

for i,v in enumerate(mylist):
  print i,v

###Pair up value in lists

for v1,v2 in zip(None,v1List,v2List):
  print v1,v2

###Product of lists

import itertools
for v1,v2 in list(itertools.product(v1List,v2List))
  print v1,v2 

pop()

1. l.pop() is to get and remove the last item from the list.
2. l.pop(i) is to get and remove the ith item from the list.