Learn Python By Practice — dict，pythondict,def dictTest

Learn Python By Practice — dict，pythondict,def dictTest

def dictTest():    # 字典是Python中一个高效的key/value哈希表结构，字典的表示使用花括号，这不同于列表的圆括号    mydict = {}    mydict["a"] = "apple"    mydict["b"] = "banana"    mydict["p"] = "pear"    print(mydict)    print(mydict["a"])    print(mydict["b"])    # 改变key为"b"的元素的value    mydict["b"] = "ballon"    print(mydict["b"])    if "p" in mydict:   # 检查成员资格，避免KeyErro        print(mydict["p"])    print(mydict.get("p"))  # 与[]访问等价    # 遍历key    print("遍历字典的key：")    for key in mydict:        print(key)    # 遍历key，与上面等价    for key in mydict.keys():        print(key)    # 遍历value    print("遍历字典的value：")    for val in mydict.values():        print(val)    # 遍历key、value    print("遍历字典：")    for key in mydict.keys():        print(key, mydict[key])    # 字典转换成(key, value)元组    print("以(key, value)元组方式访问字典：")    print(mydict.items()) # dict_items([('b', 'ballon'), ('a', 'apple'), ('p', 'pear')])    for item in mydict.items():        print(item)    print("以(key, value)元组方式访问字典2：")    for k, v in mydict.items():        print(k, v)    # 字典格式化    myhash = {}    myhash["word"] = "giraffe"    myhash["count"] = 4    msg = "%(count)d tall %(word)s are eating leaves." % myhash    print("字典格式化：" + msg)    # del用于删除列表和字典的元素    name = "zhangsan"    del name # 不存在name变量了    mylist = ["a", "b", "c", "d", "e"]    del mylist[0]    print("删除列表第一个元素后：" + str(mylist))    del mylist[-2] # 删除元组倒数第2个元素    print("删除列表倒数第2个元素后：" + str(mylist))    del mydict["a"]    print("删除字典key为a的元素后：" + str(mydict))def main():    dictTest()if __name__=="__main__":    main()