Convert string to dictionary in Python

We have worked on different problems based on strings and dictionaries. In this tutorial, we will see how we can convert a string to a dictionary in Python.

Before that, let's have a quick recall of strings and dictionaries.

Strings are defined as a sequence of characters and are denoted using single or double inverted commas.

For example-

We can check the data type of the above variables using type().

Dictionaries are defined as a data structure in Python that uses key-value pairs which are enclosed in curly braces.

We can access the values present in the dictionary with the help of respective keys.

The example of a dictionary is-

Now let's list out the methods that can convert a string to a dictionary.

1. Using loads()
2. Using literal_eval()
3. Using Generator Expressions

It's time to discuss each one of them in detail-

Using json.loads()

The following program shows how we can convert a string to a dictionary using json.loads()

Output:

String_1 is  {"subj1":"Computer Science","subj2":"Physics","subj3":"Chemistry","subj4":"Mathematics"}
The resultant dictionary is  {'subj1': 'Computer Science', 'subj2': 'Physics', 'subj3': 'Chemistry', 'subj4': 'Mathematics'}

Explanation:

Let's understand what we have done in the above program-

1. In the first step, we have imported the json module.
2. After this, we have initialized the string that we would like to convert.
3. Now we have simply passed 'string_1' as a parameter in loads().
4. Finally, in the last step, we have displayed the resultant dictionary.

Using ast.literal_eval()

Now we will see how ast.literal_eval can help us to meet our objective.

The following program illustrates the same-

Output:

String_1 is  {"subj1":"Computer Science","subj2":"Physics","subj3":"Chemistry","subj4":"Mathematics"}
The resultant dictionary is  {'subj1': 'Computer Science', 'subj2': 'Physics', 'subj3': 'Chemistry', 'subj4': 'Mathematics'}

Explanation:

Let's understand what we have done in the above program-

1. In the first step, we have imported the ast module.
2. After this, we have initialized the string that we would like to convert.
3. Now we have simply passed 'string_1' as a parameter in literal_eval().
4. Finally, in the last step, we have displayed the resultant dictionary.

Using Generator Expressions

Finally, in the last example we will discuss how generator expressions can be used.

Let's study the given program carefully.

Output:

String_1 is  subj1 - 10 , subj2 - 20, subj3 - 25, subj4 - 14
The resultant dictionary is:  {'subj1': 10, 'subj2': 20, 'subj3': 25, 'subj4': 14}
<class 'dict'>

It's time to check the explanation of this approach-

1. In the first step, we have declared a string that has values paired with a hyphen, and each pair is separated with a comma. This information is important since it will act as a great tool in obtaining the desired output.
2. Further, we have used strip() and split() in the for loop so that we get the dictionary in the usual format.
3. Finally, we have printed the dictionary we created and verified its type using type().

Conclusion

In this tutorial, we explored the conversion methods of string to the dictionary.