Lambdas in Python does not play by the same rules as anonymous functions in MATLAB<\/p>\n\n\n\n
It’s kind of a mixed love-and-hate situation for both. Either design choice will be confusing for some use cases. I was at first thrown off by MATLAB’s anonymous function’s full variable capture<\/em> behavior, then after I get used to it, Python’s Lambda’s non-closure tripped me. Even in the official FAQ<\/a>, it address the surprise that people are not getting what they expected creating lambdas in a for-loop.<\/p>\n\n\n\n To enable capture in Python, you assign the value you wanted to capture to a lambda input argument (aka, using a bound variable<\/em> as an intermediary and initialize it with the free variable <\/em>that needs to be captured), then use the intermediary in the expression. For example:<\/p>\n\n\n\n I usually keep the usage of nested functions to the minimum, even in MATLAB, because effectively it’s kind of a compromised ‘global’ between nested levels, or a little bit like protected<\/em> classes in C++. It breaks encapsulation (intentionally) for functions in your inner circle (nest).<\/p>\n\n\n\n It’s often useful for coding up GUI in MATLAB quick because you need to share access to the UI controls within the same group. For GUI that gets more complicated, I actually avoided nested functions altogether and used *appdata() to share UI object handles.<\/p>\n\n\n\nlambda: ser.close() # does not capture 'ser'\nlambda s=ser: s.close() # 'ser' is captured by s.<\/pre>\n\n\n\n
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