Astropy.io.fits - 版本历史

2023年7月9日 (日) 01:47 Shen

2023-07-09T01:47:26Z

@@ 第49行： / 第49行： @@
     # Change something in hdul.
     hdul.flush()
 ==fits文件打开过多错误==
@@ 第65行： / 第75行： @@
 :*del hdu.data
 :*hdu = fits.open(fits_name,memmap=False) #打开fits文件数目比较多的情况下

Shen：/* header */

2023-07-09T01:46:57Z

header

←上一版本		2023年7月9日 (日) 01:46的版本
第5行：		第5行：

	==header==		==header==
		⚫	>>> hdr=hdulist[0].header
	*each element of an HDUList is an HDU object with .header and .data attributes, which can be used to access the header and data portions of the HDU.
			>> list(hdr.keys())
⚫	>>> hdulist[0].header~~['targname']~~
			>>> hdr['targname']
		⚫	>>> header[:2] #只看前面两个
		⚫	>>> hdr.set('observer', 'Edwin Hubble') #添加header


	*To see the entire header as it appears in the FITS file (with the END card and padding stripped), simply enter the header object by itself, or print(repr(header)):
			* FITS标准使用的特定结构关键字集随HDU类型的不同而不同,还有许多其他保留的关键字，例如用于数据缩放的关键字，或用于表的列属性的关键字，如FITS标准中所述。其中大多数都可以通过Column或HDU对象的属性访问，例如用HDU .name设置EXTVER的 EXTNAME或HDU.ver。结构关键字将作为通用操作的结果进行检查和/或更新。例如,关键字NAXIS*从数据形状(.data.shape)中设置，BITPIX从数据类型(.data.dtype)中设置,调用HDU的验证方法(PrimaryHDU.verify()),一些关键字可以自动修复。
	*It’s also possible to view a slice of the header:

⚫	>>> header[:2]
			===comment/hitory===
	*Another way to either update an existing card or append a new one is to use the Header.set() method:
			>>> hdr['history'] = 'I updated this file 2/26/09'
⚫	>>> ~~prihdr~~.set('observer', 'Edwin Hubble')
			>>> hdr['comment'] = 'Edwin Hubble really knew his stuff'
			>>> hdr['comment'] = 'I like using HST observations'
			>>> hdr['history']
			I updated this file 2/26/09
			>>> hdr['comment']
			Edwin Hubble really knew his stuff
			I like using HST observations
			>>> hdr['comment'][1] = 'I like using JWST observations'
			>>> hdr['comment']
			Edwin Hubble really knew his stuff
			I like using JWST observations

	==fits table 的读与写==		==fits table 的读与写==

Shen：/* fits table 的读与写 */

2023-07-09T01:34:48Z

fits table 的读与写

@@ 第15行： / 第15行： @@
 ==fits table 的读与写==
 *读
  hdu = fits.open('SFH_LMC3_out.fits')
  hdu.info() #看看哪些hdu
  data=hdu[1].data
  data.columns #看看有那些列
 ==fits文件打开过多错误==

Shen：创建页面，内容为“ >>> hdulist = fits.open('input.fits') >>> hdulist.info() ==header== *each element of an HDUList is an HDU object with .header and .data attributes, which can be…”

2023-07-09T01:23:00Z

创建页面，内容为“ >>> hdulist = fits.open('input.fits') >>> hdulist.info() ==header== *each element of an HDUList is an HDU object with .header and .data attributes, which can be…”

新页面

>>> hdulist = fits.open('input.fits')
>>> hdulist.info()

==header==
*each element of an HDUList is an HDU object with .header and .data attributes, which can be used to access the header and data portions of the HDU.
>>> hdulist[0].header['targname']

*To see the entire header as it appears in the FITS file (with the END card and padding stripped), simply enter the header object by itself, or print(repr(header)):
*It’s also possible to view a slice of the header:
>>> header[:2]
*Another way to either update an existing card or append a new one is to use the Header.set() method:
>>> prihdr.set('observer', 'Edwin Hubble')

==fits table 的读与写==
*写
from astropy.table import Table
t=Table([Bage,fzbin,Age_weight2],names=('Age','z','weights'))
t.write('SFH_LMC3_out.fits',format='fits')
*读
hdu = fits.open('SFH_LMC3_out.fits')
hdu.info() #看看哪些hdu
data=hdu[1].data
data.columns #看看有那些列
Bage=data. Field('Age')

==fits文件打开过多错误==
* [https://docs.astropy.org/en/stable/io/fits/appendix/faq.html#i-am-opening-many-fits-files-in-a-loop-and-getting-oserror-too-many-open-files]
* fits.close()
* 可能还根系统设置有关
ulimit -a
ulimit -n 100000
vim /etc/security/limits.conf
* 把python的软限制编程硬限制,参见 [https://bbs.huaweicloud.com/blogs/108323],下面方法貌似也不管用
import resource
soft, hard = resource.getrlimit(resource.RLIMIT_NOFILE)
resource.setrlimit(resource.RLIMIT_NOFILE, (hard, hard))
*lsof -p 进程id > openfiles.log命令，获得当前占用句柄的全部详情进行分析
* 实测这两个效果不好（python 3.8）
:*del hdu.data
:*hdu = fits.open(fits_name,memmap=False) #打开fits文件数目比较多的情况下

==fits image读写==
n = np.arange(100.0)
hdu = fits.PrimaryHDU(n)
hdu.writeto('new2.fits')
hdu.writeto('new2.fits')
*如果超过一个hdu
>>> hdul = fits.HDUList([hdu])
>>> hdul.writeto('new1.fits')

Astropy.io.fits - 版本历史

2023年7月9日 (日) 01:47 Shen

Shen：​/* header */

Shen：​/* fits table 的读与写 */

Shen：​创建页面，内容为“ >>> hdulist = fits.open('input.fits') >>> hdulist.info() ==header== *each element of an HDUList is an HDU object with .header and .data attributes, which can be…”

Shen：/* header */

Shen：/* fits table 的读与写 */

Shen：创建页面，内容为“ >>> hdulist = fits.open('input.fits') >>> hdulist.info() ==header== *each element of an HDUList is an HDU object with .header and .data attributes, which can be…”