无法使用自然命名检索PyTables中的数据集 [英] Cannot retrieve Datasets in PyTables using natural naming
问题描述
我是PyTables的新手,我想使用自然命名从HDF5检索数据集,但使用以下输入却遇到此错误:
f = table.open_file( filename.h5, r)
f.root.group-1.dataset-1.read()
group /
没有一个名为 group
$ b
,如果我尝试:
f.root.group\-1.dataset\-1.read()
group /
没有一个名为 group
换行符后出现意外字符
我无法更改组名,因为来自实验的大数据。
您不能在自然命名中使用减号(连字符),因为它不是有效的字符作为Python变量名( group-1
和 dataset-1
看起来像是减法运算!)请参见以下讨论:
为什么-python-does-not-allow-hyphens
如果您有使用此命名约定的组和数据集,则必须使用 file.get_node()
方法来访问它们。这是一个简单的代码片段来演示。第一部分创建2个组和表(数据集)。 #1在组和表名称中使用 _
,而#2在组和表名称中使用-
。第二部分使用自然命名访问数据集#1,并使用 file.get_node()
导入表为tb
导入numpy为np
#创建具有2个组和数据集的h5文件:
# '/ group_1','ds_1':支持自然命名
#'/ group-2','ds-2':不支持自然命名
h5f = tb.open_file('SO_55211646.h5', 'w')
h5f.create_group('/','group_1')
h5f.create_group('/','group-2')
mydtype = np.dtype([[('a',float),('b',float),('c',float)])
h5f.create_table('/ group_1','ds_1',说明= mydtype)
h5f.create_table('/ group-2','ds-2',description = mydtype)
#关闭,然后重新打开文件
h5f。 close()
h5f = tb.open_file('SO_55211646.h5','r')
testds_1 = h5f.root.group_1.ds_1.read()
print(testds_1.dtype)
#以下是无效的Python语句:
#testds-2 = h5f.root.group-2.ds-2.read()
#print(testds-2 .dtype)
testds_2 = h5f.get_node('/ group-2','ds-2')。read()
打印(testds_2.dtype)
h5f.close()
I'm new in PyTables and I want to retrieve a dataset from a HDF5 using natural naming but I'm getting this error using this input:
f = tables.open_file("filename.h5", "r")
f.root.group-1.dataset-1.read()
group /
does not have a child named group
and if I try:
f.root.group\-1.dataset\-1.read()
group /
does not have a child named group
unexpected character after line continuation character
I can't change names in the groups because is big data from an experiment.
You can't use the minus (hyphen) sign with Natural Naming because it's not a valid character as a Python variable name (group-1
and dataset-1
look like a subtraction operation!) See this discussion:
why-python-does-not-allow-hyphens
If you have groups and datasets that use this naming convention, you will have to use the file.get_node()
method to access them. Here's a simple code snippet to demonstrate. The first part creates 2 groups and tables (datasets). #1 uses _
and #2 uses -
in the group and table names. The second part accesses dataset #1 with Natural Naming, and dataset #2 with file.get_node()
import tables as tb
import numpy as np
# Create h5 file with 2 groups and datasets:
# '/group_1', 'ds_1' : Natural Naming Supported
# '/group-2', 'ds-2' : Natural Naming NOT Supported
h5f = tb.open_file('SO_55211646.h5', 'w')
h5f.create_group('/', 'group_1')
h5f.create_group('/', 'group-2')
mydtype = np.dtype([('a',float),('b',float),('c',float)])
h5f.create_table('/group_1', 'ds_1', description=mydtype )
h5f.create_table('/group-2', 'ds-2', description=mydtype )
# Close, then Reopen file READ ONLY
h5f.close()
h5f = tb.open_file('SO_55211646.h5', 'r')
testds_1 = h5f.root.group_1.ds_1.read()
print (testds_1.dtype)
# these aren't valid Python statements:
#testds-2 = h5f.root.group-2.ds-2.read()
#print (testds-2.dtype)
testds_2 = h5f.get_node('/group-2','ds-2').read()
print (testds_2.dtype)
h5f.close()
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