I have 2 lists one containing float values and second has number of occurrences of values from first list. How can I create a new list, that have value times occurrences?
values = [10.5,20.2, 50.0]
occ = [3,5,1]
Result should be [10.5,10.5,10.5,20.2,20.2,20.2,20.2,20.2,50.0]
CodePudding user response：
You can use zip to iterate both the lists in parallel, then just repeat the items number of times and add it to the resulting list, something like this:
result = []
for v,m in zip(values,occ):
result.extend([v for _ in range(m)])
result
[10.5, 10.5, 10.5, 20.2, 20.2, 20.2, 20.2, 20.2, 50.0]
Or the list-comprehension as suggested in comment:
[v for v, c in zip(values, occ) for _ in range(c)]
[10.5, 10.5, 10.5, 20.2, 20.2, 20.2, 20.2, 20.2, 50.0]
CodePudding user response：
You can use zip with a nested list comprehension:
values = [10.5,20.2, 50.0]
occ = [3,5,1]
result = [x for x, y in zip(values, occ) for _ in range(y)]
Alternatively, without using range:
result = [elem for x, y in zip(values, occ) for elem in [x] * y]
Output:
[10.5, 10.5, 10.5, 20.2, 20.2, 20.2, 20.2, 20.2, 50.0]
CodePudding user response：
You could use this:
sum(([v]*m for v, m in zip(values, occ)), [])
Not recommended for large lists. Actually not really recommended at all.
CodePudding user response：
The pythonic way would be using zip in a list comprehension as demonstrated multiple times.
You can simple loops and enumerate() to a similar effect - but it results in more lines of code:
values = [10.5,20.2, 50.0]
occ = [3, 5, 1]
result = []
# enumerate returns a tuple: position, value
# of all values of the iterable you give it
for index, times in enumerate(occ):
# use the index to get the value from the other list you
# have and append it multiple times
for _ in range(times):
result.append(values[index])
print(result)
Output:
[10.5, 10.5, 10.5, 20.2, 20.2, 20.2, 20.2, 20.2, 50.0]