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How do I add, modify, and delete elements in a dictionary
Knowledge depot: In Python programs — keys are unique, but values can be repeated!
Add data to the dictionary:
(1) Base operation not 6!
Here’s what you need to know — in Python, a dictionary is a dynamic structure into which you can add “key/value” pairs at any time.
To add data to a dictionary, specify the name of the dictionary, enclose the key in brackets, and specify the value of the key.
We use this method to add our math and English scores to xiao Hong:
dict = {'line generation': "99"."Data analysis": "99"."Probability theory": "98"} # create a dictionary
dict['mathematics'] = 100 Add dictionary 1
dict['English'] = 99 # add dictionary 2
print(dict) Print the dict values
print('Xiao Hong's math score is:'.dict['mathematics']) # show your math score
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Note Note: The order in which the key-value pairs are arranged is different from the order in which they are added. Because Python doesn’t care about the order in which key-value pairs are added, it only cares about the relationship between keys and values!!
② Modify the dictionary:
(1) Base operation not 6!
First specify the dictionary name, and then use brackets to match the key to be changed to the new value. The bright-eyed students will notice that this is like adding data to a dictionary. In fact, we can be very sure to tell you that it is exactly the same, so we can summarize a rhyme: ** there is this key to modify, no add!
The teacher suddenly found that I was wrong in a place when I changed the test paper for Xiaohong. She should have been 100 points, so now we have to modify the dictionary for Xiaohong. The code:
dict = {'line generation': "99"."Data analysis": "99"."Probability theory": "98"} # create a dictionary
dict['line generation'] = 100
print('Xiao Hong's real grade is:'.dict['line generation'])
print(dict)
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(2) Items commonly used!
** update the dictionary, merge the old dictionary with the new dictionary, and overwrite the old dictionary if the key is repeated. ** code:
dict = {'name':'dry'.'age':18.'sex':'male'}
dict.update({'height': 195.'age': 20})
print(dict)
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Delete data from dictionary:
(1) Base operation not 6!
In Python programs, for information that is no longer needed in the dictionary, the del statement can be used to remove the corresponding “key value” pair information completely. To delete data from a dictionary using the DEL statement, you must specify the dictionary name and the key to delete.
Now we don’t need to count the score of xiaohong’s line generation, let’s see how I can delete this key value pair. The code:
dict = {'line generation': "99"."Data analysis": "99"."Probability theory": "98"} # create a dictionary
del dict['line generation'] # delete key 'line'
print(dict) Display the dict elements
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(2) Items commonly used!
(1) clear clear dictionary — usage: dictionary name
dict = {'name':'dry'.'age':18.'sex':'male'}
dict.clear()
print(dict)
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The code:
dict = {'name':'dry'.'age':18.'sex':'male'}
a = dict.pop('name')
print('The pop-up key has the value:', a)
print(dict)
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dict = {'name':'dry'.'age':18.'sex':'male'}
a = dict.popitem() # # is equivalent to pushing out, but one key/value pair at a time
print('Delete the last key-value pair in the dictionary:',a)
print(dict)
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🔆 In The End!
| Start now, stick to it, a little progress a day, in the near future, you will thank you for your efforts! |
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