Replacement index 1 out of range for positional args tuple

Replacement index 1 out of range for positional args tuple #

The Python "IndexError: Replacement index 1 out of range for positional args tuple" occurs when we use the format() method without providing a value for all replacement fields. To solve the error, make sure to provide a value for each replacement field.

Here is an example of how the error occurs.

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# ⛔️ IndexError: Replacement index 1 out of range for positional args tuple
my_str = 'Her name is {} {}'.format('Alice')

Notice that we only passed a value for the first replacement field.

To solve the error, make sure to specify a value for each replacement field.

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my_str = 'Her name is {} {}'.format('Alice', 'Smith')

print(my_str)  # 👉️ 'Her name is Alice Smith'

If you have an iterable (e.g. a list or a tuple), use an asterisk to unpack the iterable's items.

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my_list = ['Alice', 'Smith']

my_str = 'Her name is {} {}'.format(*my_list)

print(my_str)  # 👉️ 'Her name is Alice Smith'

The asterisk unpacks the items of the iterable in the call to the format() method.

The str.format method performs string formatting operations.

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first = 'James'

last = 'Doe'

result = "His name is {0} {1}".format(first, last)

print(result)  # 👉️ "His name is James Doe"

The string the method is called on can contain replacement fields specified using curly braces {}.

You can also use keyword arguments instead of positional ones.

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first = 'James'

last = 'Doe'

result = "His name is {f} {l}".format(f=first, l=last)

print(result)  # 👉️ "His name is James Doe"

If you decide to use positional arguments with numeric indices, make sure to start from 0, e.g. {0} as indices are zero-based in Python.

Alternatively, you can use a formatted string literal to concatenate strings.

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first = 'James'

last = 'Doe'

result = f'His name is {first} {last}'

print(result)  # 👉️ "His name is James Doe"

Make sure to wrap expressions in curly braces - {expression}.

This should be your preferred approach as formatted string literals are a more recent addition to Python and offer a much easier to read syntax.