1. Dictionaries Dictionaries Are similar to other compound types except that they can use any immutable type as an index. As an example, we will create a dictionary to translate English words into Spanish. For this dictionary, the indices are strings.

2. 1- create a dictionary One way to create a dictionary is to start with the empty dictionary and add elements. The empty dictionary is denoted {}: >> var={} >> var[‘ key1 ’] = ‘value’ >> var [‘key 2’] = ‘value 2’ The first assignment creates a dictionary named var ; the other assignments add new elements to the dictionary. We can print the current value of the dictionary in the usual way: >> print var >> {‘var2’: ‘value 2’ , ‘var1’ : ‘value1’ }

4. Hint br />The key-value pairs are not in order! Fortunately, there is no reason to care about the order, since the elements of a dictionary are never indexed with integer indices. Instead, we use the keys to look up the corresponding values

5. 2- Dictionary operations * The del statement removes a key-value pair from a dictionary.

6. ** change any value *** The len function also works on dictionaries; it returns the number of key-value pairs:

7. 3-Dictionary methods >> .keys() >> .values() >> .items() >> .has_key()

9. Hint br />If you try to call a method without specifying an object, you get an error. In this case, the error message is not very helpful: >>> has_key('one') Name Error: has_key

10. Copying If you want to modify a dictionary and keep a copy of the original, use the copy method ,,,

11. Copying >> user and copy refer to the same object; copy refers to a fresh copy of the same dictionary. If we modify user, copy is also changed:

12. ahmed karim user copy ali user copy كل من ال و تؤشر على نفس العناصر أو عناوين العناصر في ال RAM

13. If we modify copy, opposites is unchanged:

14. nice program

15. counting the number of letter in word ..

16. Good luck ! By /salma subh