IDL to SunPy Translation

This page provides some quick notes on translating from IDL to Sunpy.

Function Mappings

• SSW/IDL to Python/SunPy
• anytim goes to sunpy.util.parse_time
• histogram reverse indices ?
• referencing and dereferencing a pointer ?
• file_search ?
• value_locate ?
• total goes to array.sum()
• mtotal ?
• integration
• int_tabulated ?
• f_div ?
• uniq/get_uniq ?

You can find a larger list here.

The IDL where command

The where command is a very useful function in IDL which returns an array of indices which meet a particular requirement. For example,

a = indgen(100)
index = where(a LT 30)
b = a[index]

The b array now contains only those elements in a less than 30. The equivalent in Python/Sunpy is

import numpy as np
a = np.arange(0,100)
b = a[a  30]

This is possible because the relationship, a < 30, returns a list of indices which are labeled as True or False. This list can then be used to index any other array. More discussion on this topic can be found here.