比较两个值是否相等

= 和 == 的区别

• =：赋值运算符，把右边的值交给左边变量
• ==：相等比较运算符，判断两边值是否相等，返回布尔值 True / False

>>> 1 == 1
True
>>> 1 == 2
FalseCode language: PHP (php)

数字比较（不同数值类型）

int整数 和 float浮点数可以互相比较，只看实际数值大小

>>> 1.23 == 1
False
>>> 1.0 == 1
TrueCode language: PHP (php)

字符串用==比较

• 完整比对：全部字符一模一样才返回True，大小写、空格不一样也不相等
• 支持切片局部比对，只对比字符串其中一段内容

a = "Mackintosh apples"
c = "Golden Delicious apples"

# 切片截取末尾的apples做对比
a[-len("apples"):-1] == c[-len("apples"):-1]
# TrueCode language: PHP (php)

a = "red apple"
b = "green apple"
d = "red apple"
print(a == b)   # False
print(a == d)   # TrueCode language: PHP (php)

序列（列表list）比较规则

同一个索引位置上，每一个元素全部相等，列表才相等；元素顺序不一样，结果就是False

apple1 = ["a","b","c"]
apple2 = ["a","b","c","d"]
apple3 = ["a","c","b"]

print(apple1 == apple2) # False，长度不同
print(apple1 == apple3) # False，元素顺序不一样Code language: PHP (php)

字典dict比较规则

只要两个字典所有键‑值对完全一样，字典就相等；字典不受内部键的排列顺序影响。

tuesday_breakfast_sold = {"pancakes":10, "french toast": 4, "bagels":32,"omelets":12, "eggs and sausages":13}
wednesday_breakfast_sold = {"pancakes":8, "french toast": 5, "bagels":22,"omelets":16, "eggs and sausages":22}
thursday_breakfast_sold = {"pancakes":10, "french toast": 4, "bagels":32,"omelets":12, "eggs and sausages":13}

print(tuesday_breakfast_sold == wednesday_breakfast_sold) # False
print(tuesday_breakfast_sold == thursday_breakfast_sold) # TrueCode language: PHP (php)

总结

== 可以用于：数字、字符串、列表、字典；

• 列表：顺序、长度、每个元素全部一致才相等
• 字典：键值对全部一致就相等，不在乎内部顺序