How do I sum tuples in a list where the first value is the same?

by

How about this? You can read about collections.defaultdict.

>>> from collections import defaultdict
>>> testDict = defaultdict(int)
>>> p = [('AAPL', 50), ('AAPL', -50), ('RY', 100), ('RY', -43)]
>>> for key, val in p:
        testDict[key] += val


>>> testDict.items()
[('AAPL', 0), ('RY', 57)]

More Related Contents:

  1. Python script to ping linux server
  2. Print string without single quotes & brackets
  3. Python String concatenation with in double quotes [closed]
  4. How to extract numbers from a string in Python?
  5. Python’s many ways of string formatting — are the older ones (going to be) deprecated?
  6. How to make IPython notebook matplotlib plot inline
  7. Create a directly-executable cross-platform GUI app using Python
  8. What’s the scope of a variable initialized in an if statement?
  9. Reading an Excel file in python using pandas
  10. Cannot install pygame in Pycharm
  11. Concatenating two one-dimensional NumPy arrays
  12. Python Pandas: Get index of rows which column matches certain value
  13. How to write inline if statement for print?
  14. Pandas deleting row with df.drop doesn’t work
  15. How to replace Django’s primary key with a different integer that is unique for that table
  16. Python: sort function breaks in the presence of nan
  17. Python multiprocessing: Permission denied
  18. h5py not sticking to chunking specification?
  19. Calling a PyGame Function, from clicking a Object-Orientated PyGame Button [duplicate]
  20. ‘NOT NULL constraint failed’ after adding to models.py
  21. Creating intersecting images in matplotlib with imshow or other function
  22. Using a loop to create multiple variables
  23. Flask App: Update progress bar while function runs
  24. Replacing Header with Top Row
  25. Pyodbc error Data source name not found and no default driver specified paradox
  26. What is the time complexity of Python list’s count() function?
  27. Python: How to move or copy Azure Blob from one container to another
  28. how can i remove notifications and alerts from browser? selenium python 2.7.7
  29. Python multiprocessing application is getting stuck in docker container
  30. Using a loop in Python to name variables [duplicate]

Leave a Comment