TheRealFakeNews
Reputation: 8153
How to add a value from a dict to a list only if the dict has a specific key?
Say I have a class Node, with attributes left, right, val. Then suppose we have internal and leaf, where leaf has None for left and right. Then iterating through my_list = [internal, leaf], I only want to add the child nodes to an array only if they exist, so I would do something like
[x.left if x.left is not None for x in my_list]
Is something like this possible? When I try this I get a invalid syntax error
Upvotes: 1
Views: 33
Answers (1)
BrokenBenchmark
Reputation: 19242
You're almost there! You need to switch the ordering of the for and if clauses:
[x.left for x in my_list if x.left is not None]
Upvotes: 1
Related Questions
- How to Add Another Item in A List That's A Value for a Dictionary if the Key has already been used
- how to add list value to dictionary to key if the key is already exists
- Python: How to conditionally add item to list within dictionary
- Compare and add new key in dict using list Comprehension in Python
- Python add key to list of dictionary if key doesn't exist
- Add dict key from list if list value isn't already a dict key
- Python: How to append list item to dictionary if item equals key?
- Append to value in dict if key exists / convert value to list then append
- Add value to key, depending on if the value is in another key
- Python: How to append a value in a dict to a list if the value is found in another list