《笨办法学Python3》练习二十四：更多练习

练习代码

print("Let's practice everything.")
print('You\'d need to know \'bout escapes with \\ that do:')
print('\n newlines and \t tabs.')

poem = """
\tThe lovely world
with logic so firmly planted
cannot discern \n the needs of love
nor comprehend passion from intuition
and requires an explanation
\n\t\twhere there is none.
"""

print("--------------")
print(poem)
print("--------------")

five = 10 - 2 + 3 - 6
print(f"This should be five: {five}")

def secret_formula(started):
    jelly_beans = started * 500
    jars = jelly_beans / 1000
    crates = jars / 100
    # return a tuple
    return jelly_beans, jars, crates

start_point = 10000
# print(type(secret_formula(start_point)))
# unpack the tuple
beans, jars, crates = secret_formula(start_point)

# remember that this is another way to format a string
print("With a starting point of : {}".format(start_point))
# it's just like with an f""string
print(f"We'd have {beans} beans, {jars} jars, and {crates} crates.")

start_point = start_point / 10
print("We can also do that this way:")
formula = secret_formula(start_point)
# this is an easy way to apply a list to a format string
print("We'd have {} beans, {} jars, and {} crates.".format(*formula))

Study Drills

1. Make sure to do your checks: read it backward, read it out loud, and put comments above confusing parts.

2. Break the file on purpose, then run it to see what kinds of errors you get. Make sure you can fix it.

补充

1.  # this is an easy way to apply a list to a format string
    print("We'd have {} beans, {} jars, and {} crates.".format(*formula))
   

   这里作者说“这是一个便于将list中的值赋给格式化字符串的方法。”，但确切地说，函数secret_formula返回的是一个元组(tuple)，而*formula也是一种unpack操作。