# ast --- Abstract syntax trees — Literals

> A constant value. The value attribute of the Constant literal contains the Python object it represents. The values represented can be instances of str, bytes, int, float, complex, and bool, and the constants None and Ellipsis. The kind attribute is an optional string. For string literals with a u pr

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- Canonical URL: <https://wikikv.com/k/ref-python-b94e70188add08b9f890>
- Knowledge kind: `reference`
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- Updated: `2026-08-16T09:32:14.542391+00:00`
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## Knowledge

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A constant value. The value attribute of the Constant literal contains the Python object it represents. The values represented can be instances of str, bytes, int, float, complex, and bool, and the constants None and Ellipsis.

The kind attribute is an optional string. For string literals with a u prefix, kind is set to 'u'. For all other constants, kind is None.

Node representing a single formatting field in an f-string. If the string contains a single formatting field and nothing else the node can be isolated otherwise it appears in JoinedStr.

value is any expression node (such as a literal, a variable, or a function call). conversion is an integer

format_spec is a JoinedStr node representing the formatting of the value, or None if no format was specified. Both conversion and format_spec can be set at the same time.

An f-string, comprising a series of FormattedValue and Constant nodes.

Node representing a template string literal, comprising a series of Interpolation and Constant nodes. These nodes may be any order, and do not need to be interleaved.

Node representing a single interpolation field in a template string literal.

value is any expression node (such as a literal, a variable, or a function call). This has the same meaning as FormattedValue.value. str is a constant containing the text of the interpolation expression.

format_spec is a JoinedStr node representing the formatting of the value, or None if no format was specified. Both conversion and format_spec can be set at the same time. This has the same meaning as FormattedValue.format_spec.

A list or tuple. elts holds a list of nodes representing the elements. ctx is Store if the container is an assignment target (i.e. (x,y)=something), and Load otherwise.

A set. elts holds a list of nodes representing the set's elements.

A dictionary. keys and values hold lists of nodes representing the keys and the values respectively, in matching order (what would be returned when calling dictionary.keys() and dictionary.values()).

When doing dictionary unpacking using dictionary literals the expression to be expanded goes in the values list, with a None at the corresponding position in keys.

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