Python Comprehensions

# pattern for list comprehension
names2 = []
for name in names:
    if len(name) == 4:  # filter
        names2.append(name.title())  # title is mapping
names2

['John', 'Paul']

names2 = [name.title() for name in names if len(name) == 4]
names2

['John', 'Paul']

# Dict Comprehensions
types = {'name': str, 'age': int, 'address': str}
new_names = {}
for t in types:
    new_names[t] = t.title()
new_names

{'name': 'Name', 'age': 'Age', 'address': 'Address'}

new_names = {t: t.title() for t in types}

{'name': 'Name', 'age': 'Age', 'address': 'Address'}

# Set Comprehensions
uniq_names = {name for name in names if len(name) == 4}
uniq_names

{'john', 'paul'}

# Generator Expression
lazy_names = (name for name in names if len(name) == 4)
list(lazy_names)

['john', 'paul']

References