Pythonic way to find maximum value and its index in a list?
There are many options, for example:
import operator
index, value = max(enumerate(my_list), key=operator.itemgetter(1))
I think the accepted answer is great, but why don't you do it explicitly? I feel more people would understand your code, and that is in agreement with PEP 8:
max_value = max(my_list)
max_index = my_list.index(max_value)
This method is also about three times faster than the accepted answer:
import random
from datetime import datetime
import operator
def explicit(l):
max_val = max(l)
max_idx = l.index(max_val)
return max_idx, max_val
def implicit(l):
max_idx, max_val = max(enumerate(l), key=operator.itemgetter(1))
return max_idx, max_val
if __name__ == "__main__":
from timeit import Timer
t = Timer("explicit(l)", "from __main__ import explicit, implicit; "
"import random; import operator;"
"l = [random.random() for _ in xrange(100)]")
print "Explicit: %.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
t = Timer("implicit(l)", "from __main__ import explicit, implicit; "
"import random; import operator;"
"l = [random.random() for _ in xrange(100)]")
print "Implicit: %.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
Results as they run in my computer:
Explicit: 8.07 usec/pass
Implicit: 22.86 usec/pass
Other set:
Explicit: 6.80 usec/pass
Implicit: 19.01 usec/pass