《利用Python进行数据分析·第3版》中文新版上市《利用Python进行数据分析》这本书并不是以学习Python编程为主,所以只是用了两章的篇幅简单介绍了Python的基础知识,但对知识的梳理很好。如果想完整学习Python,入门Python的书有不少,推荐这几本《Python编程:从入门到实践》(这本书读前10章就够了)、《Python Cookbook...
一、错误处理 在程序运行的过程中,如果发生了错误,可以事先约定返回一个错误代码,这样,就可以知道是否有错,以及出错的原因。在操作系统提供的调用中,返回错误码非常常见。比如打开文件的函数open(),成功时返回文件描述符(就是一个整数),出错时返回-1。 用错误码来表示是否出错十分不便,因为函数本身应该返回的正常结...
下面是一个示例函数,它尝试从字典中获取一个键的值,如果该键不存在,则返回None: AI检测代码解析 def get_value_from_dict(d, key): return d.get(key) my_dict = {'a': 1, 'b': 2} value = get_value_from_dict(my_dict, 'c') if value is None: print("Key 'c' does not exist in th...
")89ifpeople>cats:10print("Not many cats! The world is saved!")1112ifpeople<dogs:13print("The world is drooled on!")1415ifpeople>dogs:16print("The world is dry!")171819dogs+=52021ifpeople>=dogs:22print("People are greater than or equal to dogs.")2324ifpeople<=dogs:25print(...
logic="startswith")ifdollar_i_filesisnotNone: processed_files = process_dollar_i(tsk_util, dollar_i_files) write_csv(report_file, ['file_path','file_size','deleted_time','dollar_i_file','dollar_r_file','is_directory'], processed_files)else:print("No $I files found") ...
andasassertasyncawaitbreakclasscontinuedefdelelifelseexceptFalsefinallyforfromglobalifimportinislambdaNonenonlocalnotorpassraisereturnTruetrywhilewithyield Python二级考试涉及到的保留字一共有22个。选学5个:None、finally、lambda、pass、with。 Python中的保留字也是大小写敏感的。举例:True为保留字,而true则...
How to handle indexes on other axis (or axes).ignore_index : bool, default FalseIf True, do not use the index values along the concatenation axis. Theresulting axis will be labeled 0, ..., n - 1. This is useful if you areconcatenating objects where the concatenation axis does not ...
Python does this in constant time without having to scan through every item by using hash functions. When Python looks up a key foo in a dict, it first computes hash(foo) (which runs in constant-time). Since in Python it is required that objects that compare equal also have the same ...
None -- remove first occurrence of value. | Raises ValueError if the value is not present...
A string can be non-empty but contain only whitespace characters. To handle this, you might want to useif not my_string.strip()to check for the presence of non-whitespace characters. How does strip() work in checking for an empty string?