node - bruno-beloff/scs_analysis GitHub Wiki
docs > software repositories > scs_analysis > commands > manipulating nodes within JSON documents
DESCRIPTION
The node utility is used to extract a node or nodes from within a JSON document tree. Data is presented as a sequence of documents on stdin, and the extracted node(s) are passed to stdout. Alternatively to stdin, a single JSON document can be read from a file. The extracted node may be a leaf node or an internal node.
Using the --rename flag, a single internal or leaf node may be relocated in the document tree prior to node selection for output. The rename TO field is always output.
If the --merge flag is used, then the values of two fields A and B are joined with the JOIN string. The combined string has the location A in the document tree. If A is present and B is not present then the value is that of A alone. If B is present and A is not present, then B is discarded.
By default, only the specified nodes are passed to the output. In the --exclude mode, all nodes are passed to stdout, except the specified nodes. In the default mode, if no node path is specified, the whole input document is passed to stdout. In the --exclude mode, if no node path is specified, then nothing is output.
By default, output is in the form of a sequence of JSON documents, separated by newlines. If the array (-a) option is selected, output is in the form of a JSON array - the output opens with a '[' character, documents are separated by the ',' character, and the output is terminated by a ']' character.
Alternatively, if the node is an array or other iterable type, then it may be output as a sequence (a list of items separated by newline characters) according to the -s flag.
The ordering of output nodes is as follows:
- Exclude mode - by input nodes
- Default mode - by nodes specified on the command line
WARNING: node ordering is determined by the internal node structure of the input document. Thus the specified ordering: a.b.c, x.b.c, a.b.d would be rendered as: a.b.c, a.b.d, x.b.c
SYNOPSIS
node.py [-r FROM TO] [-m A B JOIN] [-x] [-a] [-s] [-f FILE] [-i INDENT] [-v] [NODE_1 .. NODE_N]
| Options | |
|---|---|
| --version | show program's version number and exit |
| -h, --help | show this help message and exit |
| -r RENAME, --rename=RENAME | move the node at FROM to TO |
| -m MERGE, --merge=MERGE | merge A and B |
| -x, --exclude | include all nodes except the named one(s) |
| -a, --array | output the sequence of input JSON documents as array |
| -s, --sequence | output the contents of the input array node(s) as a sequence |
| -f FILENAME, --file=FILENAME | read from FILE instead of stdin |
| -i INDENT, --indent=INDENT | pretty-print the output with INDENT |
| -v, --verbose | report narrative to stderr |
EXAMPLES
csv_reader.py climate.csv | node.py -x val.bar
DOCUMENT EXAMPLE - INPUT
{"val": {"hmd": 73.5, "tmp": 10.8, "bar": ""}, "rec": "2019-02-17T08:56:53Z"}
{"val": {"hmd": 73.6, "tmp": 10.8, "bar": ""}, "rec": "2019-02-17T08:57:53Z"}
DOCUMENT EXAMPLE - OUTPUT
default mode:
{"val": {"hmd": 73.5, "tmp": 10.8}, "rec": "2019-02-17T08:56:53Z"}
{"val": {"hmd": 73.6, "tmp": 10.8}, "rec": "2019-02-17T08:57:53Z"}
array mode:
[{"val": {"hmd": 73.5, "tmp": 10.8}, "rec": "2019-02-17T08:56:53Z"}, {"val": {"hmd": 73.6, "tmp": 10.8}, "rec": "2019-02-17T08:57:53Z"}]