检查变量是否为空

function checkIfEmpty(variable) {
    if (variable === null || variable === undefined || variable === "") {
        console.log("变量为空");
    } else if (typeof variable === "number" && isNaN(variable)) {
        console.log("变量是 NaN");
    } else if (typeof variable === "boolean" && !variable) {
        console.log("变量是 false");
    } else {
        console.log("变量不为空");
    }
}

// 测试
checkIfEmpty(null);       // 变量为空
checkIfEmpty(undefined);  // 变量为空
checkIfEmpty("");         // 变量为空
checkIfEmpty(0);          // 变量不为空
checkIfEmpty(NaN);        // 变量是 NaN
checkIfEmpty(false);      // 变量是 false
checkIfEmpty("Hello");    // 变量不为空

def check_if_empty(variable):
    if variable is None:
        print("变量为空")
    elif isinstance(variable, str) and variable == "":
        print("变量为空字符串")
    elif isinstance(variable, (int, float)) and variable == 0:
        print("变量为零")
    else:
        print("变量不为空")

# 测试
check_if_empty(None)       # 变量为空
check_if_empty("")         # 变量为空字符串
check_if_empty(0)          # 变量为零
check_if_empty("Hello")    # 变量不为空