Didot leverages the PocketCsvReader parser and interprets CSV headers containing . and [], dynamically transforming them into structured nested dictionaries or lists, enabling seamless representation of hierarchical data.
Default CSV Dialect
The parser assumes the following characteristics for the CSV file:
- Delimiter: The default column delimiter is a comma (,).
- Quotation: Fields containing delimiters, line breaks, or special characters are enclosed in double quotes (“).
- Escape Character: Double quotes within a quoted field are escaped by doubling them (“”).
- Header Row: The first row of the CSV file must contain column headers, which define the structure of the resulting nested dictionary.
- Case Sensitivity: Headers are case-sensitive.
- Row Order: Rows with the same parent-level fields are grouped together in the final output. The order of rows in the CSV affects the resulting data structure.
Name.Fullname,Name.Acronym,Founded
NASA,National Aeronautics and Space Administration,1958-07-29
Special Header Syntax in Didot
Dot Notation (.)
A dot (.) in a header is interpreted by the parser as indicating a nested property structure.
Each segment before a dot represents a key in a nested dictionary. The final segment represents the value assigned within that dictionary.
Example of nested properties
| Header | Interpretation |
|---|---|
Name.Fullname |
Creates a dictionary Name with a key Fullname. |
Name.Acronym |
Adds a key Acronym to the Name dictionary. |
Founded |
Adds a top-level key Founded. |
is the equivalent of this JSON representation
{
"Name": {
"Fullname": "NASA",
"Acronym": "National Aeronautics and Space Administration"
},
"Founded": "1958-07-29"
}
List Syntax ([])
Square brackets ([]) in a header indicate that the corresponding property belongs to a list of dictionaries.
- Headers containing
[]represent list elements. - Each row with the same parent-level fields contributes to the same list.
- Nested properties of list items are denoted by combining
[]with dot notation.
Example of list
| Header | Interpretation |
|---|---|
Buildings[].Name |
Creates a list Buildings where each item has a key Name. |
Buildings[].Type |
Adds a key Type to each Buildings list item. |
Buildings[].Location |
Adds a key Location to each Buildings list item. |
is the equivalent of this JSON representation
{
"Buildings": [
{
"Name": "NASA Headquarters",
"Type": "Administration and Policy",
"Location": "300 E Street SW, Washington, DC 20546"
},
{
"Name": "Johnson Space Center",
"Type": "Human Spaceflight Training, Research, and Mission Control",
"Location": "2101 NASA Parkway, Houston, TX 77058"
}
]
}
Combining . and []
Dot notation and square brackets can be combined in Didot to describe deeply nested structures, such as lists within nested dictionaries.
Example of combination
| Header | Interpretation |
|---|---|
Buildings[].Details.Address.City |
Adds a nested dictionary Details to each Buildings list item. |
Buildings[].Details.Address.ZipCode |
Adds a key ZipCode to Address in each Buildings list item. |
is the equivalent of this JSON representation
{
"Buildings": [
{
"Details": {
"Address": {
"City": "Washington",
"ZipCode": "20546"
}
}
},
{
"Details": {
"Address": {
"City": "Houston",
"ZipCode": "77058"
}
}
}
]
}
Behavior of Rows with Repeated Parent-Level Fields
In Didot, rows with the same values for all non-list fields are considered part of the same top-level object. List fields ([]) for such rows are appended to the corresponding lists.
Name.Fullname,Name.Acronym,Founded,Buildings[].Name,Buildings[].Type
NASA,National Aeronautics and Space Administration,1958-07-29,NASA Headquarters,Administration and Policy
NASA,National Aeronautics and Space Administration,1958-07-29,Johnson Space Center,Human Spaceflight Training, Research, and Mission Control
Resulting Structure
[
{
"Name": {
"Fullname": "NASA",
"Acronym": "National Aeronautics and Space Administration"
},
"Founded": "1958-07-29",
"Buildings": [
{
"Name": "NASA Headquarters",
"Type": "Administration and Policy"
},
{
"Name": "Johnson Space Center",
"Type": "Human Spaceflight Training, Research, and Mission Control"
}
]
}
]
