Question

I need to have my dictionary keys in this format ‘/ cat/’ but i keep getting multiple forward slashes. Here is my code:

 # Defining the Digraph method #
 def digraphs(s):
      dictionary = {}
      count = 0;
      while count <= len(s):
          string = s[count:count + 2]
          count += 1
          dictionary[string] = s.count(string)
      for entry in dictionary:
          dictionary['/' + entry + '/'] = dictionary[entry]
          del dictionary[entry]
      print(dictionary)
 #--End of the Digraph Method---#

Here is my output:

i do this:

digraphs(‘my cat is in the hat’)

{'///in///': 1, '/// t///': 1, '/// c///': 1, '//s //': 1, '/my/': 1, '/n /': 1, '/e /': 1, '/ h/': 1, '////ha////': 1, '//////': 21, '/is/': 1, '///ca///': 1, '/he/': 1, '//th//': 1, '/t/': 3, '//at//': 2, '/t /': 1, '////y ////': 1, '/// i///': 2}

Answer 1

In Python, you generally shouldn’t iterate over objects while modifying them. Instead of modifying your dictionary, make a new one:

new_dict = {}

for entry in dictionary:
    new_dict['/' + entry + '/'] = dictionary[entry]

return new_dict

Or more compactly (Python 2.7 and above):

return {'/' + key + '/': val for key, val in dictionary.items()}

An even better approach would be to skip creating your original dictionary in the first place:

# Defining the Digraph method #
def digraphs(s):
    dictionary = {}

    for count in range(len(s)):
        string = s[count:count + 2]
        dictionary['/' + string + '/'] = s.count(string)

    return dictionary
#--End of the Digraph Method---#