Commit4112718

authored

Add a more elaborate description to the side effects section

1 parent9d712ab commit4112718Copy full SHA for 4112718

File tree

+10

-2

lines changed

+10

-2

lines changed

Lines changed: 10 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -549,17 +549,24 @@ If you can do this, you will be happier than the vast majority of other programm`
`549`	`549`	`Bad:`
`550`	`550`
`551`	`551`	```python
`552`		`-# Global variable referenced by following function.`
`553`		`-# If another function used this name, now it'd be an array and could break.`
	`552`	`+# This is a module-level name.`
	`553`	`+# It's good practice to define these as immutable values, such as a string.`
	`554`	`+# However...`
`554`	`555`	`name='Ryan McDermott'`
`555`	`556`
`556`	`557`	`defsplit_into_first_and_last_name() ->None:`
	`558`	`+# The use of the global keyword here is changing the meaning of the`
	`559`	`+# the following line. This function is now mutating the module-level`
	`560`	`+# state and introducing a side-effect!`
`557`	`561`	`global name`
`558`	`562`	`name= name.split()`
`559`	`563`
`560`	`564`	`split_into_first_and_last_name()`
`561`	`565`
`562`	`566`	`print(name)# ['Ryan', 'McDermott']`
	`567`	`+`
	`568`	`+# OK. It worked the first time, but what will happen if we call the`
	`569`	`+# function again?`
`563`	`570`	```
`564`	`571`
`565`	`572`	`Good:`
`@@ -586,6 +593,7 @@ class Person:`
`586`	`593`	`defname_as_first_and_last(self) ->list:`
`587`	`594`	`returnself.name.split()`
`588`	`595`
	`596`	`+# The reason why we create instances of classes is to manage state!`
`589`	`597`	`person= Person('Ryan McDermott')`
`590`	`598`	`print(person.name)# 'Ryan McDermott'`
`591`	`599`	`print(person.name_as_first_and_last)# ['Ryan', 'McDermott']`

Comments

(0)