[Tutor] python equivalents for perl list operators?

[Alan Gauld]

On 23/04/16 01:15, Malcolm Herbert wrote:

>   @raw = (2, 1, 4, 3);
>   @grepped = grep { $_ >= 3 } @raw; # (4, 3)

grepped = [item for item in raw if item >= 3]

>   @mapped = map { $_ + 1 } @raw; # (3, 2, 5, 4)

mapped = [item +1 for item in raw]
or
mapped = map(lambda x: x+1, raw)

>   @sorted = sort { $a > $b } @raw; # (1, 2, 3, 4)

raw.sort()  # sorts in place
_sorted = sorted(raw)

You can add parameters to both functions to specify
sort characteristics, for example:

raw2 = [(1,'p'),(2,'e'),(3,'r'),(4,'l')]

lexical = sorted(raw2,key=lambda t:t[1])

You can use the interpreter to find out some of this
by using the help() function

help([])  # help on all list methods

help([].sort)  # help on the sort method

There are also some modules that might be of interest
to you such as itertools and functools.

You might also find the Functional Programming
topic in my tutorial useful (see below).

hth
-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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