def myFunction(name):
index = 0
list = self.getList()
index = (x => x.name == name)
return index
i want to use lamba expression to find an index of an element in a python list just as in C#. is it possible to use lambda expressions just as in C# to find an index of a specific element in python list . If so please provide an example
I think this code is closer to what you are asking for:
def indexMatching(seq, condition):
for i,x in enumerate(seq):
if condition(x):
return i
return -1
class Z(object):
def __init__(self, name):
self.name = name
class X(object):
def __init__(self, zs):
self.mylist = list(zs)
def indexByName(self, name):
return indexMatching(self.mylist, lambda x: x.name==name)
x = X([Z('Fred'), Z('Barney'), Z('Wilma'), Z('Betty')])
print x.indexByName('Wilma')
Returns 2.
The key idea is to use enumerate to maintain an index value while iterating over the sequence. enumerate(seq) returns a series of (index,item) pairs. Then when you find a matching item, return the index.
If you really want to use a lambda, the syntax is:
lambda param, list: return_value
For example, this is a lamdba that does addition:
lambda x, y: x + y
I'm not sure how this could make your function easier to write though, since this is the most obvious way:
def myFunction(name):
for i, x in enumerate(self.getList()):
if x.name == name:
return i
Your lamdba would be this though:
lamdba x: x.name == name
So one horrible way of doing this is:
def myFunction(name):
matches = [index
for index, value in enumerate(self.getList())
if value.name == name]
if matches:
return matches[0]
lambda x: x.name == name. And he doesn't want x, he wants the index of x in the list.
lista standard python list or an object?