Other statements in the notes of 'Python Basic Tutorial' 1

PRint related

print can print multiple expressions, just separate them with commas. A space will be inserted between each parameter in the result. Use + to avoid spaces, such as

>>> print 'age:',42
age: 42
>>> print 'hello'+','+'world'
hello,world

Add a comma at the end of the print statement, and the following statements will Print on the same line as the previous statement, such as

print 'hello', print 'world'

result

>>>
hello world

import related

from sometmodule import somefunc,anotherfunc,yetanotherfunc

from somemodule import * -- Import all functions in the module

import somemoudle as othermodulename -- Give the module an alias

form somemodule import somefunc ad otherfuncname -- Give the imported function an alias

Assignment related

Sequence unpacking or optional unpacking - unpack the sequence of multiple values ​​and put it into the sequence of variables, such as

>>> scoundrel = {'name':'Robin','firlfriend ':'marion'}
>>> key, value = scoundrel.popitem()
>>> key
'firlfriend'
>>> value
'marion'

chain Assignment--a shortcut for assigning the same value to multiple variables, such as

x=y=somefunction()

Incremental assignment--place the expression operator to the left of the assignment operator =, such as

x += 1

Statement block

The colon (:) is used to identify the beginning of the statement block. Each statement in the block is indented (the indentation amount is the same). When the indentation is the same as that of the closed block, it means that the current block has ended.

Threesome

pass -- You don’t have to do anything with the program.

del -- deletes the object but does not affect the value, such as

>>> x = y = [1,2]
>>> y[1] = 'p'
> >> y
[1, 'p']
>>> (most recent call last):
File "", line 1, in

x

NameError: name 'x' is not defined
>>> y

[1, 'p']

exec -- Execute a string statement

>>> exec("print 'hello, world!'")
hello, world!

eval -- Find an expression Value

>>> eval("4 + 56")

60

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