I have a list of tuples like below:
data = [(0.5, 0, 0), (0.4, 0, 0), (0.6, 0, 0)]
I want to find the maximum value over the first element of each tuple using a lambda
function. In this case, the expected result would be 0.6.
I'd usually write this like this:
>>> a = [(0.5, 0, 0), (0.4, 0, 0),(0.6, 0, 0)]
>>> max(x for x, y, z in a)
0.6
Since you have the strange requirement to use a lambda function, you can also do
>>> max(a, key=lambda x: x[0])[0]
0.6
However, this is more complicated than necessary, and other than your random requirement there is no reason to do this.
l = [(0.5, 0, 0), (0.4, 0, 0),(0.6, 0, 0)]
y = max(map(lambda x: x[0], l))
print(y)
>>> 0.6
Usually people want the item (tuple) that contains the maximum first value, rather than just the max first value. This is exactly when having a lambda
is useful:
>>> data = [(0.5, 0, 0), (0.4, 0, 0), (0.6, 0, 0)]
>>> max(data, key=lambda x: x[0])
(0.6, 0, 0)
Or the most simple - if you want only the max first value and not the tuple with the max value - is without a lambda:
>>> max(x[0] for x in data)
0.6
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.