Furious Python-Article 4-functions and modules

Python functions: in fact, they are very similar to C ++, but because they are weak languages (it feels like they are ......), remove all types of declarations, and pass the value instead of reference (at least 2.7 is ), A small number of cells are defined by def (like macro definition ......), the following is an example of Python function: it is actually very similar to C ++, but it is a weak type of language (it feels like it is ......), remove all types of declarations, and pass the value instead of reference (at least 2.7 is ), A small number of cells are defined by def (like macro definition ......), the following is an example.

Def sum (a, B): # sum is the function name. pay attention to the colon ......
C = a + B # This part is the statement block of the function.
Return c # The function ends here. like C ++, PRint sum (1, 2) # Call the function based on the function name and output the value of 1 + 2.

Lambda functions are also provided here, which are similar to the features of C ++ 11. An example of the above addition function is provided.

Sum = lambda a, B: a + B # This is the definition of the lambda function. it starts with lambda and then is the input parameter. no matter how many parameters are separated by ",", and then ": "The following is the expression print sum (1, 2)

Python module: this part of feeling has something to do with java. However, the module gives me the feeling that the header file in C ++ and the file written together with the implementation are all. the following is an example.

First, the code of the Add function module is provided. if there is a code in fun. py of the current directory

#! /Usr/bin/pythondef sum (a, B ):
C = a + B return c

The code of the main function is provided. if the name test. py exists in the current directory, use import to import the module fun (isn't this Java ......),

#! /Usr/bin/pythonimport funprint fun. sum (1, 2)

Sometimes it is very troublesome. that fun is the same as the C ++ namespace, so we can actually use sum through from... import the import statement to the current space and give the code

#! /Usr/bin/pythonfrom fun import sumprint sum (1, 2)

Sometimes there may be a path strength problem. for now, make sure that the imported module is in the same directory as the main program.

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