A boolean list from ranges of True values (start and end), without using a for loop [closed]-CodePudding

For example I want to convert this list containing ranges

x=[[1,4],
   [6,7],
   [9,9]]

to a boolean list

x=[False, True, True, True, True, False, True, True, False, True]

This is obviously possible using a for loop. However, I am looking for a other options that are faster and better (one-liners are welcome e.g. maybe a list comprehension). Ideally, I am looking for some way that could also be applicable to a pandas series.

CodePudding user response：

A hopefully efficient way using numpy:

low, high = np.array(x).T[:,:, None] # rearrange the limits into a 3d array in a convenient shape
a = np.arange(high.max()   1) # make a range from 0 to 9
print(((a >= low) & (a <= high)).any(axis=0))

CodePudding user response：

inds = [[i for i in range(a, b   1)] for a, b in x]
inds = [el for ar in inds for el in ar]
[i in inds for i in range(max(inds)   1)]
# [False, True, True, True, True, False, True, True, False, True]

inds = pandas.Series([[i for i in range(a, b   1)] for a, b in x]).explode()
pandas.Series(numpy.arange(inds.max()   1)).isin(inds)
# 0    False
# 1     True
# 2     True
# 3     True
# 4     True
# 5    False
# 6     True
# 7     True
# 8    False
# 9     True
# dtype: bool