import os, tarfile, math, random, sys, getopt

## SEQUENCES AND SETS

def indices(x, seq):
    '''List of indices in seq where x is found.'''
    return [pos for pos, item in enumerate(seq) if item == x]

def distance2(vec1, vec2):
    '''Square of the euclidian distance between the vectors.'''
    return sum([(x - y)**2 for x,y in zip(vec1, vec2)])

def distance(vec1, vec2):
    '''Euclidian distance between the vectors.'''
    return math.sqrt(distance2(vec1, vec2))

def ran_bin_vec(length):
    '''A vector of len length with random 0s and 1s.'''
    return [random.randrange(2) for x in range(length)]

def union(sets):
    '''The union of multiple sets in a sequence.'''
    return reduce(lambda x, y: x | y, sets)

def intersection(sets):
    '''The intersection of multiple sets in a sequence.'''
    return reduce(lambda x, y: x & y, sets)

# Get rid of this on later versions because it overrides built-in 'any'
def any(pred, seq):
    '''True if any member of the sequence or iterator satisfies the predicate.'''
    for x in seq:
        if pred(x):
            return True
    return False

def some(pred, seq):
    '''True if any member of the sequence or iterator satisfies the predicate.'''
    for x in seq:
        px = pred(x)
        if px:
            return px
    return False

def every(pred, seq):
    '''True if every member of the sequence or iterator satisfies the predicate.'''
    for x in seq:
        if not pred(x):
            return False
    return True

def reduce_lists(lists):
    '''Flatten a list of lists (doesn't mutate lists).'''
    return reduce(lambda x, y: x + y, lists)

def remove_dups(seq):
    '''Make a copy of seq with no duplicate elements.'''
    copy = seq[:]
    for p,x in enumerate(seq):
        if x in seq[p+1:]:
            copy.remove(x)
    return copy

## MATH

def normalize(vector):
    '''Make the vector (really a list) length 1.0.'''
    total = math.sqrt(sum([x**2 for x in vector]))
    for i in range(len(vector)):
        vector[i] /= total

def dot_product(v1, v2):
    '''Dot product of the two vectors.'''
    return sum([x1 * x2 for x1, x2 in zip(v1, v2)])

def threshold(inp, thresh, min_val, max_val):
    '''Simple threshold function.'''
    if inp >= thresh:
        return max_val
    else:
        return min_val

def sigmoid(inp, thresh, bias):
    '''Sigmoid function (0 < y < 1) with threshold and bias.'''
    return 1.0 / (1.0 + math.exp(bias * (-inp + thresh)))

def sigmoid_slope(x):
    '''Slope of the sigmoid with output x.'''
    return x * (1.0 - x)

## ARGMAX

def argmax(seq, func):
    '''Element of seq with the highest value for func.'''
    best = seq[0]
    best_score = func(best)
    for x in seq:
        x_score = func(x)
        if x_score > best_score:
            best, best_score = x, x_score
    return best

def argmax2(seq, func):
    '''Element and value for seq with the highest value for func.'''
    best = seq[0]
    best_score = func(best)
    for x in seq:
        x_score = func(x)
        if x_score > best_score:
            best, best_score = x, x_score
    return (best, best_score)

## FILES, DIRECTORIES

def tarpy(direc = '.', filename = 'files', others = ()):
    '''Make gzipped tar archive called filename for .py files in direc and others.'''
    tar = tarfile.open(filename + ".tgz", "w:gz")
    for fl in [f for f in os.listdir(direc) if f[-3:] == '.py']:
        tar.add(fl)
    for o in others:
        tar.add(o)
    tar.close()

# To change directories, do
# >>> os.chdir(path)
#
# To list files in a directory, do
# >>> os.listdir(path)
# (Use '.' for current directory.)
#
# For the current directory, do
# >>> os.getcwd()