如何根据4个变量在python中进行大小写切换

# 定义4个变量
var1 = "Hello World"
var2 = "UPPERCASE"
var3 = "lowercase"
var4 = "MiXeD CaSe"

# 使用lower()方法将变量转换为小写形式
var1_lower = var1.lower()
var2_lower = var2.lower()
var3_lower = var3.lower()
var4_lower = var4.lower()

# 使用upper()方法将变量转换为大写形式
var1_upper = var1.upper()
var2_upper = var2.upper()
var3_upper = var3.upper()
var4_upper = var4.upper()

# 打印结果
print("var1_lower:", var1_lower)
print("var2_lower:", var2_lower)
print("var3_lower:", var3_lower)
print("var4_lower:", var4_lower)
print("var1_upper:", var1_upper)
print("var2_upper:", var2_upper)
print("var3_upper:", var3_upper)
print("var4_upper:", var4_upper)

var1_lower: hello world
var2_lower: uppercase
var3_lower: lowercase
var4_lower: mixed case
var1_upper: HELLO WORLD
var2_upper: UPPERCASE
var3_upper: LOWERCASE
var4_upper: MIXED CASE