python - 如何将参数传递给 Python 模块中的主函数？

Question

我最近开始学习更多关于 Python 包和模块的知识。我目前正忙于更新我现有的模块，以便它可以作为脚本运行或作为模块导入到我的其他代码中。我不确定如何在我的模块中构造我的输入参数并将它们传递到我的模块中的 main() 函数。

我已经编写了我的 ma​​in() 函数并在 if __name__ == '__main__' 下调用它并传递输入参数。输入目前是硬编码的，以显示我正在努力实现的目标。任何有关如何正确构造用户将传递的输入参数的帮助，然后将传递到主函数，我们将不胜感激。

如前所述，当我直接使用或作为模块导入我的其他代码并从那里运行时，我正在尝试能够将以下内容用作脚本。如果我将它作为模块导入，我会在导入时调用 ma​​in() 函数吗？在我编写以下内容时，以下结构是否正确？任何建议表示赞赏。

'''
Created on March 12, 2017

Create a new ArcHydro Schema

File Geodatabase and Rasters

Folder

@author: PeterW
'''
# import site-packages and modules
import re
from pathlib import Path
import arcpy

# set environment settings
arcpy.env.overwriteOutput = True


def archydro_rasters_folder(workspace):
    """Create rasters folder directory
    if it doens't already exist"""
    model_name = Path(workspace).name
    layers_name = re.sub(r"\D+", "Layers", model_name)
    layers_folder = Path(workspace, layers_name)
    if layers_folder.exists():
        arcpy.AddMessage("Rasters folder: {0} exists".format(layers_name))
    else:
        layers_folder.mkdir(parents=True)
        arcpy.AddMessage("Rasters folder {0} created".format(layers_name))


def archydro_fgdb_schema(workspace, schema, dem):
    """Create file geodatabase using XML
    schema and set coordinate system based
    on input DEM if it doesn't already exist"""
    model_name = Path(workspace).name
    fgdb = "{0}.gdb".format(model_name)
    if arcpy.Exists(str(Path(workspace, fgdb))):
        arcpy.AddMessage("{0} file geodatabase exists".format(fgdb))
    else:
        new_fgdb = arcpy.CreateFileGDB_management(str(workspace), fgdb)
        import_type = "SCHEMA_ONLY"
        config_keyword = "DEFAULTS"
        arcpy.AddMessage("New {0} file geodatabase created".format(fgdb))
        arcpy.ImportXMLWorkspaceDocument_management(new_fgdb, schema,
                                                    import_type,
                                                    config_keyword)
        arcpy.AddMessage("ArcHydro schema imported")
        projection = arcpy.Describe(dem).spatialReference
        projection_name = projection.PCSName
        feature_dataset = Path(workspace, fgdb, "Layers")
        arcpy.DefineProjection_management(str(feature_dataset),
                                          projection)
        arcpy.AddMessage("Changed projection to {0}".format(projection_name))


def main(workspace, dem, schema):
    """main function to create rasters folder
    and file geodatabase"""
    archydro_rasters_folder(workspace)
    archydro_fgdb_schema(schema, dem, workspace)

if __name__ == '__main__':
    main(workspace = r"E:\Projects\2016\01_Bertrand_Small_Projects\G113268\ArcHydro\Model04",
         dem = r"E:\Projects\2016\01_Bertrand_Small_Projects\G113268\ArcHydro\DEM2\raw",
         schema = r"E:\Python\Masters\Schema\ESRI_UC12\ModelBuilder\Schema\Model01.xml")

更新时间:2013 年 3 月 17 日

以下是我根据 Jonathan 的建议更新的 Python 模块:

'''
Created on March 12, 2017

Create a new ArcHydro Schema

File Geodatabase and Rasters

Folder

@author: PeterW
'''
# import site-packages and modules
import re
from pathlib import Path
import arcpy
import argparse

# set environment settings
arcpy.env.overwriteOutput = True


def rasters_directory(workspace):
    """Create rasters folder directory
    if it doens't already exist"""
    model_name = Path(workspace).name
    layers_name = re.sub(r"\D+", "Layers", model_name)
    layers_folder = Path(workspace, layers_name)
    if layers_folder.exists():
        arcpy.AddMessage("Rasters folder: {0} exists".format(layers_name))
    else:
        layers_folder.mkdir(parents=True)
        arcpy.AddMessage("Rasters folder {0} created".format(layers_name))


def fgdb_schema(workspace, schema, dem):
    """Create file geodatabase using XML
    schema and set coordinate system based
    on input DEM if it doesn't already exist"""
    model_name = Path(workspace).name
    fgdb = "{0}.gdb".format(model_name)
    if arcpy.Exists(str(Path(workspace, fgdb))):
        arcpy.AddMessage("{0} file geodatabase exists".format(fgdb))
    else:
        new_fgdb = arcpy.CreateFileGDB_management(str(workspace), fgdb)
        import_type = "SCHEMA_ONLY"
        config_keyword = "DEFAULTS"
        arcpy.AddMessage("New {0} file geodatabase created".format(fgdb))
        arcpy.ImportXMLWorkspaceDocument_management(new_fgdb, schema,
                                                    import_type,
                                                    config_keyword)
        arcpy.AddMessage("ArcHydro schema imported")
        projection = arcpy.Describe(dem).spatialReference
        projection_name = projection.PCSName
        feature_dataset = Path(workspace, fgdb, "Layers")
        arcpy.DefineProjection_management(str(feature_dataset),
                                          projection)
        arcpy.AddMessage("Changed projection to {0}".format(projection_name))


def model_schema(workspace, schema, dem):
    """Create model schema: rasters folder
    and file geodatabase"""
    rasters_directory(workspace)
    fgdb_schema(schema, dem, workspace)


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Create a ArcHydro schema')
    parser.add_argument('--workspace', metavar='path', required=True,
                        help='the path to workspace')
    parser.add_argument('--schema', metavar='path', required=True,
                        help='path to schema')
    parser.add_argument('--dem', metavar='path', required=True,
                        help='path to dem')
    args = parser.parse_args()
    model_schema(workspace=args.workspace, schema=args.schema, dem=args.dem)

Answer 1

这对我来说看起来是正确的，是的，如果你想把它用作一个模块，你会导入 main.不过，以更具描述性的方式命名可能会更好。

阐明 __main__ 和函数 main() 的工作原理。当您执行一个模块时，它将有一个存储在 __name__ 中的名称。如果您将模块作为脚本单独执行，它将具有名称 __main__。如果您将它作为模块的一部分执行，即将它导入另一个模块，它将具有该模块的名称。

main() 函数可以任意命名，这不会影响您的程序。它在小脚本中通常被命名为main，但如果它是较大代码体的一部分，它就不是一个特别好的名字。

在作为脚本运行时允许用户输入参数方面，我会考虑使用 argparse或 click

argparse 如何工作的示例。

if __name__ == '__main__':
    import argparse

    parser = argparse.ArgumentParser(description='Create a ArcHydro schema')
    parser.add_argument('--workspace', metavar='path', required=True,
                        help='the path to workspace')
    parser.add_argument('--schema', metavar='path', required=True,
                        help='path to schema')
    parser.add_argument('--dem', metavar='path', required=True,
                        help='path to dem')
    args = parser.parse_args()
    main(workspace=args.workspace, schema=args.schema, dem=args.dem)