#!/usr/bin/env python
# coding: utf-8

# # Asides
# 
# This is a notebook that is a collection of 'cool things'.
# 
# Either Language or Library features demonstrated in isolation, or 'clever' algorithms with better explanations.
# 
# ## F-strings
# 
# Introduced in [Python 3.6](https://docs.python.org/3/whatsnew/3.6.html#whatsnew36-pep498), f-strings are now the simplest *and* fastest way to print values in interesting formats; 

# In[1]:


val = 'world'
print(f'hello {val}')


# However, considering that the f-string effectively puts the entire kernel at your disposal, becareful not to get too clever, otherwise you end up with unreadable messes

# In[2]:


print(f'Hello {input("What is your name?")}!')


# ## Walrus Operators
# 
# Introduced in [Python 3.8](https://docs.python.org/3/whatsnew/3.8.html), a new language construct was added; the walrus operator; `:=`
# 
# To understand why this is cool; start off with the case where it doesn't exist. 
# 
# For instance, we have some basic conditional logic; if a list is too long to be processed, complain about it
# 

# In[3]:


def check_input(a):
    if len(a) > 10:
        raise ValueError(f'List is too long; got {len(a)}, expected < 10')
    else:
        return a
    
check_input(range(100))
    


# But we're calling `len` twice when we really don't have to (and `len` can have some nasty side effects on some types of iterators)
# 
# The walrus operator allows us to 'grab' the value of the output of `len` while also comparing it; like this

# In[ ]:


def check_input(a):
    a_len = len(a)
    if a_len > 10:
        raise ValueError(f'List is too long; got {a_len}, expected < 10')
    else:
        return a
    
check_input(range(100))


# In[4]:


def check_input(a):
    if (a_len :=len(a)) > 10:
        raise ValueError(f'List is too long; got {a_len}, expected < 10')
    else:
        return a
    
check_input(range(100))


# However, be careful with your brackets 

# In[7]:


def check_input(a):
    if (a_len :=len(a) > 10):
        raise ValueError(f'List is too long; got {a_len}, expected < 10')
    else:
        return a
    
check_input(range(100))


# In[ ]: