Using Lambda with lists

Question

I am trying to check if a string object is in a list. Simply written as: ``` if str in list: ``` The problem I am facing is that this list, is not a list of strings, but a list of tables. I understand that nothing is going to happen if I do this comparison directly. What I would like to do is access an attribute of each of these tables called 'Name'. I could create a new list, and do my comparison against that: ``` newList = [] for i in list: newList.append(i.Name) ``` But as I am still a newbie, I am curious about Lambda's and wondered if it would be possible to implement that instead? something like (... but probably nothing like): ``` if str in list (lambda x: x.Name): ```

Accepted Answer

Lambdas pretty much doesn't needed here. You can just check it directly:

```
for table in my_list:
    if string in table.Name:
        #do stuff
```

Or using list comprehension, if you want it that way:

```
if string in [table.Name for table in my_list]:
    #do interesting stuff
```

More efficiently, as @Tim suggested, use a generator expression:

```
if string in (table.Name for table in my_list):
```

But if you insist in using lambdas:

```
names = map(lambda table: table.Name, my_list)
if string in names:
    #do amazing stuff!
```

Here's a little demo:

```
>>> class test():
    def __init__(self, name):
        self.Name = name

>>> my_list = [test(n) for n in name]
>>> l = list(map(lambda table: table.Name, my_list)) #converted to list, it's printable.
>>> l
['a', 'b', 'c']
```

Also, avoid using names of built in functions such as `str`, `list` for variable names. It will override them!

Hope this helps!

Using Lambda with lists

Solution

Problem