Some handy tricks/tips in Python.

python-tips.py

"""
Here are some useful tips/tricks in Python.

Credit: https://gist.github.com/neubig
"""

# To assign unique inter ids to words do the following.
from collections import defaultdict
wids = defaultdict(lambda: len(wids))

# Now when you check for a word in wids, if it does not exist then it will be added
# after assigning the incremented integer ids.

# Softmax function 
def softmax(x):
    e = np.exp(x - np.max(x))  # prevent overflow
    return e / np.sum(e)
    
# Tanh and derivative
def tanh_prime(x):
    y = np.tanh(x)
    y_prime = 1 - (y * y)
    return y, y_prime