变量名应该遵循一定的命名约定,采用驼峰命名法或下划线命名法:驼峰命名法指的是将每个单词的首字母大写,单词之间不使用下划线,例如myVariableName;下划线命名法指的是使用小写字母和下划线来分隔单词,例如my_variable_name。在Python中,推荐使用下划线命名法(也称为蛇形命名法) 变量名只能包含字母、数字和下划线_,不能以数字
TypeError Raised when a function or operation is applied to an object of an incorrect type. UnboundLocalError Raised when a reference is made to a local variable in a function or method, but no value has been bound to that variable. UnicodeError Raised when a Unicode-related encoding or decod...
Python 自带了csv模块,所以我们可以导入它 ➊ 而不必先安装它。 要使用csv模块读取一个 CSV 文件,首先使用open()函数 ➋ 打开它,就像您处理任何其他文本文件一样。但不是在open()返回的File对象上调用read()或readlines()方法,而是将其传递给csv.reader()函数 ➌。这将返回一个reader对象供您使用。注意,...
This module is imported into the main.py file. Let’s see the code and implementation in detail. Module.py File import module module.hello() print(module.__file__) Here, the module is imported from the module.py file. The __file__ variable is used to print the path. The hello()...
Activating a virtual environment modifies the PATH and shell variables to point to the specific isolated Python set-up you created. PATH is an environmental variable in Linux and other Unix-like operating systems that tells the shell which directories to search for executable files (i.e., ready...
(envValue=ZTP_STATUS_END, ops_conn=None): """Set the ZTP process status. input: envValue int Environment variable value, which can be true or false output: ret int Operation result """ logging.info("Set the value of envZtpStatus to {} .".format(envValue)) if envValue not in ['...
py 1 key error Traceback (most recent call last): File "foo.py", line 19, in <module> bad() File "foo.py", line 17, in bad print(e) UnboundLocalError: local variable 'e' referenced before assignment What has just happened here? The “problem” is that, in Python 3, the ...
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Bash warning: There are some systems where theBASH_ENVvariable is configured to point to.bashrc. On such systems, you should almost certainly put theeval "$(pyenv init - bash)"line into.bash_profile, andnotinto.bashrc. Otherwise, you may observe strange behaviour, such aspyenvgetting into ...
struct { PyObject ob_base; Py_ssize_t ob_size; /* Number of items in variable part...