Suppose I have the list
R=['$x_{0}$','$x_{1}$','$x_{2}$','$a_{3}$','$\\varepsilon_{4}$','$a_{5}$','$\\varepsilon_{6}$']
how can I make a condition looking like
if R[i]== a (the index is not relevant only the family name of the variable)
If v is in R then you can use e.g. the condition v[:3] == '$a_' to check that the first three characters in v are $a_.
sage: [v for v in R if v[:3] == '$a_']
['$a_{3}$', '$a_{5}$']
sage: for v in R:
....: if v[:3] == '$a_':
....: print(v)
....:
$a_{3}$
$a_{5}$
Or you can use the condition v.startswith('$a_') if you don't feel like counting to 3.
Asked: 2022-03-01 22:14:56 +0100
Seen: 197 times
Last updated: Mar 01 '22
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