python - How to search through dictionaries? - Stack Overflow
2015年1月30日 · I'm making a simple program that has a dictionary that includes four names as keys and the respective ages as values. What I'm trying to do is that if the user enters the a name, the program checks if it's in the dictionary and if it is, …
python - Get key by value in dictionary - Stack Overflow
how slow is this: slower than a simple search, but not nearly as slow as you'd think - on a 'straight' 100000 entry dictionary, a 'fast' search (i.e. looking for a value that should be early in the keys) was about 10x faster than reversing the entire dictionary, and a 'slow' search (towards the end) about 4-5x faster.
How to Find Item in Dictionary Collection? - Stack Overflow
This is an inefficient and a little bit strange way to find something by key in a Dictionary. Looking things up for a Key is the basic function of a Dictionary. But the key has to exist.
Search a list of dictionaries in Python - Stack Overflow
Conclusion: Clearly having a dictionary of dicts is the most efficient way to be able to search in those cases, where you know say you will be searching by id's only. interestingly using filter is the slowest solution.
How do I traverse and search a python dictionary?
This kind of problem is often better solved with proper class definitions, not generic dictionaries. class ProperObject( object ): """A proper class definition for each "attr" dictionary.""" def __init__( self, path, attrDict ): self.path= path self.__dict__.update( attrDict ) def __str__( self ): return "path %r, entity %r, hash %r, id %r" % ( self.path, self.entity, self.hash, self.id ...
How to check if a value exists in a dictionary? - Stack Overflow
to test if "one" is among the values of your dictionary. In Python 2, it's more efficient to use "one" in d.itervalues() instead. Note that this triggers a linear scan through the values of the dictionary, short-circuiting as soon as it is found, so this is a lot less …
Retrieving Dictionary Value Best Practices - Stack Overflow
When you call the Contains method, Dictionary does an internal search to find its index. If it returns true, you need another index search to get the actual value. When you use TryGetValue, it searches only once for the index and if found, it assigns the value to your variable.
python - Efficient Dictionary Searching? - Stack Overflow
2013年10月1日 · data_dict.keys() returns an unsorted list of keys in the dictionary. Thus each time you check to see if a given key is in the dictionary, you're doing a linear search across the list of keys (an O(n) operation). The longer your list, the longer it takes to search for a given key. Contrast this to data_dict[keyStr]. This performs a hash lookup ...
Iterating over dictionaries using 'for' loops - Stack Overflow
2010年7月21日 · As we know that in Python Dictionary as a set of key: value pairs, with the requirement that the keys are unique (within one dictionary). A pair of braces creates an empty dictionary: {}. Placing a comma-separated list of key:value pairs within the braces adds initial key:value pairs to the dictionary. No, key is not a special word in Python.
c# - Dictionary search with Linq - Stack Overflow
2011年8月30日 · we can search dictionary like. var dictionary = new Dictionary<string,string>(); dictionary.Keys.Where( key => key.Contains("a")).ToList(); but it return list. i want that linq should return true or false. so what would be the right code that search dictionary with linq. please guide.