python3 字符串居中對齊

d = {
    'key': 'value',
    'key2': 'value2',
}
s = 'key'
print(s.rjust(20))
print(s.ljust(20))

# 找出一個最長的鍵值 作爲左填充
# map 傳內置的len
w = max(map(len, d.keys()))
for k in d: print(k.ljust(w), ":", d[k])