GRASS Python Scripting Library - Revision history

Baharmon: /* Uses for read, feed and pipe, start and exec commands */ Fixed broken link

2025-02-18T22:18:05Z

Uses for read, feed and pipe, start and exec commands: Fixed broken link

← Older revision		Revision as of 22:18, 18 February 2025
Line 129:		Line 129:
	* {{pyapi\|script\|script.core\|exec_command}} doesn't use <tt>start_command()</tt> but <tt>os.execvpe()</tt>. This causes the specified command to replace the current program (i.e. the Python script), so <tt>exec_command()</tt> never returns. Similar to bash's "exec" command. This can be useful if the script is a "wrapper" around a single command, where you construct the command line and execute the command as the final step. Notes: exec_command() is rarely appropriate. You probably want run_command() instead. On Windows, exec_command() will probably require the ".exe" suffix.		* {{pyapi\|script\|script.core\|exec_command}} doesn't use <tt>start_command()</tt> but <tt>os.execvpe()</tt>. This causes the specified command to replace the current program (i.e. the Python script), so <tt>exec_command()</tt> never returns. Similar to bash's "exec" command. This can be useful if the script is a "wrapper" around a single command, where you construct the command line and execute the command as the final step. Notes: exec_command() is rarely appropriate. You probably want run_command() instead. On Windows, exec_command() will probably require the ".exe" suffix.

	If you have any other questions, you might want to look at the code ({{src\|~~lib~~/~~python~~/script/core.py}}). Most of these functions are only a few lines long.		If you have any other questions, you might want to look at the code ({{src\|python/grass/script/core.py}}). Most of these functions are only a few lines long.

	=== Hints for parse_command() ===		=== Hints for parse_command() ===

Neteler: /* Parsing tabular output */

2024-10-24T12:18:32Z

Parsing tabular output

← Older revision		Revision as of 12:18, 24 October 2024
Line 360:		Line 360:
	</source>		</source>

	=== Parsing tabular output ===		=== Parsing tabular text output ===

	Examples in Python for configurable separator for parsing their tabular text output:		Examples in Python for configurable separator for parsing their tabular text output:

Neteler: +Parsing tabular output

2024-10-24T12:18:05Z

+Parsing tabular output

← Older revision		Revision as of 12:18, 24 October 2024
Line 359:		Line 359:
	outdev = sys.stdout		outdev = sys.stdout
	</source>		</source>

			=== Parsing tabular output ===

			Examples in Python for configurable separator for parsing their tabular text output:

			* {{src\|scripts/m.proj/m.proj.py}}
			* {{src\|scripts/v.report/v.report.py}}
			* {{src\|scripts/r.out.xyz/r.out.xyz.py}}
			* {{src\|scripts/r.tileset/r.tileset.py}}

	=== Passing several floats to a single option ===		=== Passing several floats to a single option ===

⚠️Baharmon: /* Interfacing with NumPy */

2022-11-23T20:40:02Z

Interfacing with NumPy

← Older revision		Revision as of 20:40, 23 November 2022
Line 169:		Line 169:

	def main():		def main():
	map = "elevation~~.dem~~"		map = "elevation"

	# read map		# read map

⚠️Baharmon: /* Interfacing with NumPy and SciPy */

2022-11-23T20:39:33Z

Interfacing with NumPy and SciPy

← Older revision		Revision as of 20:39, 23 November 2022
Line 222:		Line 222:

	def main():		def main():
	map = "elevation~~.dem~~"		map = "elevation"

	x = garray.array()		x = garray.array(map)
	~~x.read~~(map)

	# Descriptive Statistics:		# Descriptive Statistics:

⚠️Baharmon: /* Interfacing with NumPy */

2022-11-23T20:38:59Z

Interfacing with NumPy

← Older revision		Revision as of 20:38, 23 November 2022
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	=== Interfacing with NumPy ===		=== Interfacing with NumPy ===

	The {{pyapi\|script\|script.array\|array}} module defines a <code>class array</code> which is a subclass of [http://docs.scipy.org/doc/numpy/reference/generated/numpy.memmap.html numpy.memmap] ~~with <code>.read()<~~/~~code> and <code>.write()</code> methods to read/write~~ the underlying file via {{cmd\|r.out.bin}}/{{cmd\|r.in.bin}}. Metadata can be read with {{pyapi\|script\|script.raster\|raster_info}}:		The {{pyapi\|script\|script.array\|array}} module defines a <code>class array</code> which is a subclass of [http://docs.scipy.org/doc/numpy/reference/generated/numpy.memmap.html numpy.memmap] that reads/writes the underlying file via {{cmd\|r.out.bin}}/{{cmd\|r.in.bin}}. Metadata can be read with {{pyapi\|script\|script.raster\|raster_info}}:

	Example:		Example:
Line 172:		Line 172:

	# read map		# read map
	a = garray.array()		a = garray.array(map)
	~~a.read~~(map)

	# get raster map info		# get raster map info
Line 211:		Line 210:
	'''MASK support:'''		'''MASK support:'''

	~~The function grass.script.array.read()~~ and ~~...write()~~ use r.out.bin and r.in.bin respectively. r.out.bin respects the MASK.		Reading and writing use r.out.bin and r.in.bin respectively. r.out.bin respects the MASK.

	=== Interfacing with NumPy and SciPy ===		=== Interfacing with NumPy and SciPy ===

⚠️Baharmon: Updated print statements to Python 3 in the Interfacing section

2022-03-31T01:09:31Z

Updated print statements to Python 3 in the Interfacing section

← Older revision		Revision as of 01:09, 31 March 2022
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	# get raster map info		# get raster map info
	print grass.raster_info(map)['datatype']		print(grass.raster_info(map)['datatype'])
	i = grass.raster_info(map)		i = grass.raster_info(map)

	# get computational region info		# get computational region info
	c = grass.region()		c = grass.region()
	print "rows: %d" % c['rows']		print("rows: %d" % c['rows'])
	print "cols: %d" % c['cols']		print("cols: %d" % c['cols'])

	# new array for result		# new array for result
Line 229:		Line 229:

	# Descriptive Statistics:		# Descriptive Statistics:
	print "max, min, mean, var:"		print("max, min, mean, var:")
	print x.max(), x.min(), x.mean(), x.var()		print(x.max(), x.min(), x.mean(), x.var())
	print "Skewness test: z-score and 2-sided p-value:"		print("Skewness test: z-score and 2-sided p-value:")
	print stats.skewtest(stats.skew(x))		print(stats.skewtest(stats.skew(x)))
	</source>		</source>

Neteler: updated to current API

2021-01-04T10:55:38Z

updated to current API

← Older revision		Revision as of 10:55, 4 January 2021
Line 745:		Line 745:
	=== Interface to listing maps (g.list) ===		=== Interface to listing maps (g.list) ===

	You may use the functions in [~~http~~://grass.osgeo.org/~~programming7~~/~~namespacepython_1_1script_1_1core~~.html ~~python~~.script.core.~~mlist_grouped~~()]:		You may use the functions in [https://grass.osgeo.org/grass-stable/manuals/libpython/script.html?highlight=list_grouped#script.core.list_grouped script.core.list_grouped()]:

	<source lang="python">		<source lang="python">
			# list all
	list_grouped('raster')['PERMANENT']		list_grouped('raster')['PERMANENT']
	[..., 'lakes', ..., 'slope', ...		[..., 'lakes', ..., 'slope', ...
	~~</source>~~

	~~and~~

	~~<source lang="python">~~		# list with pattern
	~~mlist_grouped~~('~~vector~~', pattern='roads')['PERMANENT']		list_grouped('vect', pattern='roads')['PERMANENT']
	['railroads', 'roadsmajor']		['railroads', 'roadsmajor']
	</source>		</source>

			For temporal data, see likewise [https://grass.osgeo.org/grass-stable/manuals/libpython/temporal.html?highlight=list_grouped#temporal.gui_support.tlist_grouped temporal.gui_support.tlist_grouped()]

	See also [[Python/pygrass#Sample_PyGRASS_scripts\|Sample PyGRASS scripts]] for an alternative solution.		See also [[Python/pygrass#Sample_PyGRASS_scripts\|Sample PyGRASS scripts]] for an alternative solution.

Neteler: added "Accessing the --quiet and --verbose flags"

2020-10-10T16:58:11Z

added "Accessing the --quiet and --verbose flags"

← Older revision		Revision as of 16:58, 10 October 2020
Line 348:		Line 348:
	</source>		</source>

			'''Accessing the --quiet and --verbose flags:'''

	'''Passing several floats to a single option~~:'''~~		See {{pyapi\|script\|script.core\|verbosity}} for the 5 verbosity levels:

			<source lang="python">
			from grass.script import core as grass

			# to hide non-error messages from subprocesses
			if grass.verbosity() <= 2:
			outdev = open(os.devnull, 'w')
			else:
			outdev = sys.stdout
			</source>

			=== Passing several floats to a single option ===

	Example:		Example:
Line 382:		Line 395:
	For more information on option definitions, see:		For more information on option definitions, see:

	~~http~~://grass.osgeo.org/programming7/gislib.html#Complete_Structure_Members_Table		https://grass.osgeo.org/programming7/gislib.html#Complete_Structure_Members_Table

	=== Example for embedding r.mapcalc (map algebra) ===		=== Example for embedding r.mapcalc (map algebra) ===

Neteler: fix URL of lib/python/script/core.py

2020-08-28T08:52:28Z

fix URL of lib/python/script/core.py

← Older revision		Revision as of 08:52, 28 August 2020
Line 129:		Line 129:
	* {{pyapi\|script\|script.core\|exec_command}} doesn't use <tt>start_command()</tt> but <tt>os.execvpe()</tt>. This causes the specified command to replace the current program (i.e. the Python script), so <tt>exec_command()</tt> never returns. Similar to bash's "exec" command. This can be useful if the script is a "wrapper" around a single command, where you construct the command line and execute the command as the final step. Notes: exec_command() is rarely appropriate. You probably want run_command() instead. On Windows, exec_command() will probably require the ".exe" suffix.		* {{pyapi\|script\|script.core\|exec_command}} doesn't use <tt>start_command()</tt> but <tt>os.execvpe()</tt>. This causes the specified command to replace the current program (i.e. the Python script), so <tt>exec_command()</tt> never returns. Similar to bash's "exec" command. This can be useful if the script is a "wrapper" around a single command, where you construct the command line and execute the command as the final step. Notes: exec_command() is rarely appropriate. You probably want run_command() instead. On Windows, exec_command() will probably require the ".exe" suffix.

	If you have any other questions, you might want to look at the code ({{src\|lib/python/core.py}}). Most of these functions are only a few lines long.		If you have any other questions, you might want to look at the code ({{src\|lib/python/script/core.py}}). Most of these functions are only a few lines long.

	=== Hints for parse_command() ===		=== Hints for parse_command() ===

	To turn this command		To turn this command
	g.rename ~~rast~~=old_name,new_name		g.rename raster=old_name,new_name
	into a g.parse_command() call, you need to consider that it is a function call with three arguments:		into a g.parse_command() call, you need to consider that it is a function call with three arguments:
	# "g.rename"		# "g.rename"
	# ~~rast~~=old_name		# raster=old_name
	# new_name		# new_name

Line 150:		Line 150:
	than as an argument separator:		than as an argument separator:

	g.parse_command("g.rename", ~~rast~~=(old_name,new_name))		g.parse_command("g.rename", raster=(old_name,new_name))

	The parentheses in a tuple value can only be omitted if it doesn't		The parentheses in a tuple value can only be omitted if it doesn't