I have a dictionary with key-value pair. My value contains strings. How can I search if a specific string exists in the dictionary and return the key that correspond to the key that contains the value.
Let's say I want to search if the string 'Mary' exists in the dictionary value and get the key that contains it. This is what I tried but obviously it doesn't work that way.
#Just an example how the dictionary may look like
myDict = {'age': ['12'], 'address': ['34 Main Street, 212 First Avenue'],
'firstName': ['Alan', 'Mary-Ann'], 'lastName': ['Stone', 'Lee']}
#Checking if string 'Mary' exists in dictionary value
print 'Mary' in myDict.values()
Is there a better way to do this since I may want to look for a substring of the value stored ('Mary' is a substring of the value 'Mary-Ann').
I am a bit late, but another way is to use list comprehension and the any function, that takes an iterable and returns True whenever one element is True :
# Checking if string 'Mary' exists in the lists of the dictionary values
print any(any('Mary' in s for s in subList) for subList in myDict.values())
If you wanna count the number of element that have "Mary" in them, you can use sum():
# Number of sublists containing 'Mary'
print sum(any('Mary' in s for s in subList) for subList in myDict.values())
# Number of strings containing 'Mary'
print sum(sum('Mary' in s for s in subList) for subList in myDict.values())
From these methods, we can easily make functions to check which are the keys or values matching.
To get the keys containing 'Mary':
def matchingKeys(dictionary, searchString):
return [key for key,val in dictionary.items() if any(searchString in s for s in val)]
To get the sublists:
def matchingValues(dictionary, searchString):
return [val for val in dictionary.values() if any(searchString in s for s in val)]
To get the strings:
def matchingValues(dictionary, searchString):
return [s for s i for val in dictionary.values() if any(searchString in s for s in val)]
To get both:
def matchingElements(dictionary, searchString):
return {key:val for key,val in dictionary.items() if any(searchString in s for s in val)}
And if you want to get only the strings containing "Mary", you can do a double list comprehension :
def matchingStrings(dictionary, searchString):
return [s for val in dictionary.values() for s in val if searchString in s]