Convert a string to a tuple without splitting in Python

Convert a string to a tuple without splitting in Python #

Use a trailing comma to convert a string to a tuple without splitting, e.g. my_tuple = (my_str,). A tuple with one item is constructed by following a value with a comma. Enclosing the value in parenthesis is not sufficient to create a tuple.

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my_str = 'one'

my_tuple = (my_str,)

print(my_tuple)  # 👉️ ('one',)
print(type(my_tuple))  # 👉️ <class 'tuple'>

# --------------------

my_tuple_2 = my_str,

print(my_tuple_2)  # 👉️ ('one',)
print(type(my_tuple_2))  # 👉️ <class 'tuple'>

We used a trailing comma to convert a string to a tuple without splitting.

If you pass the string to the tuple() class, you'd get a tuple containing the string's characters.

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print(tuple('one')) # 👉️ ('o', 'n', 'e')

The tuple() class takes an iterable (e.g. a list or a string) and creates a tuple from it.

On the other hand, we can convert a string to a tuple by adding a trailing comma after the string.

As the documentation states construction of tuples with 1 item is done by following a value with a comma.

For example, both of these variables store a tuple with 1 item only.

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my_str = 'one'

my_tuple = (my_str,)

my_tuple_2 = my_str,

It is not sufficient to wrap a single value in parenthesis to create a tuple.

The trailing comma after the value is the difference between creating a tuple (with trailing comma) or creating a value of a different type (without trailing comma).

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my_tuple_1 = ('one',)
print(my_tuple_1)  # 👉️ ('one',)
print(type(my_tuple_1))  # 👉️ <class 'tuple'>

my_str = ('one')
print(my_str)  # 👉️ 'one'
print(type(my_str))  # 👉️ <class 'str'>

The first example uses a trailing comma after the value, so we end up creating a tuple.

The second example simply encloses a value in parenthesis, so we end up creating a string.

Tuples are constructed in multiple ways:

• Using a pair of parenthesis () creates an empty tuple
• Using a trailing comma - a, or (a,)
• Separating items with commas - a, b or (a, b)
• Using the tuple() constructor

The same syntax should be used when creating a list of tuples or using tuples as dictionary keys or values.

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my_list = [('one',), ('two',), ('three',)]

print(my_list[0])  # 👉️ ('one',)
print(type(my_list[0]))  # 👉️ <class 'tuple'>

Alternatively, you can use the tuple class if you don't like the implicit behavior of creating a tuple with a trailing comma.

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my_str = 'one'

my_tuple = tuple([my_str])

print(my_tuple) # 👉️ ('one',)

This is important because had we passed a string to the class, we would get a tuple containing the string's characters.

If you aren't sure what type a variable stores, use the built-in type() class.

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my_str = 'one'
print(type(my_str))  # 👉️ <class 'str'>
print(isinstance(my_str, str))  # 👉️ True

my_tuple = (my_str,)
print(type(my_tuple))  # 👉️ <class 'tuple'>
print(isinstance(my_tuple, tuple))  # 👉️ True

The type class returns the type of an object.

The isinstance function returns True if the passed in object is an instance or a subclass of the passed in class.