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This article will explain in detail how to create and modify python global. The content of the article is of high quality, so the editor will share it with you for reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

1. Global creates a global variable in a function, which is equivalent to creating a global variable in a file.

2. Modify the global variables in the function. Because global variables are assigned / modified directly in the function, they are considered to create new local variables.

Of course, you can modify it by indexing the elements in the global variable.

Example

Global variable 1, variable 2,...

Variable 1 = assignment data

# error demonstration

The expected modified global variable 1 = data # python believes that a local variable has been created: variable 1.

# correct demonstration

Global expects the modified global variable 1 # to first tell python that this variable is also treated as a global variable at this local level.

Expected modified global variable 1 = data

Content extension:

The global variables of Python: int string, list, dic (map) can modify its value if global exists. Regardless of whether the global exists in the if or whether the if can be executed.

But if not,

If bGlobal: global g_strVal

Int string will report an error. And list dic (map) is ok.

#! / usr/bin/dev python import sys import os g_nVal = 0; g_strVal = "aaaa"; g_map = {"aaa": "111"," bbb ":" 222", "ccc": "333", "ddd": "444"} g_ls = ['await,' baked,'c'] def FixInt (bGlobal = False): if bGlobal: global g_nVal G_nVal = g_nVal + 1; def FixString (bGlobal = False): if bGlobal: global glossstrValue; # fix string value g_strVal = g_strVal + 'b'; def FixMap (bGlobal = False): if bGlobal: global gambimappings; # fix map value g_map [' aaa'] = 'aaa__' + gambistrValue; g_map [' bbb'] = 'bbb__' + g_strVal G_map ['ccc'] =' ccc__' + glossstrVal; g_map ['ddd'] =' ddd__' + glossstrVal; def FixList (bGlobal = False): if bGlobal: global galleys; g_ls.append ('1'); def PrintVal (strInfo): if strInfo: print ("= =% s ="% strInfo); print ("int value:%d"% g_nVal) Print ("string value:%s"% g_strVal); print ("map value:%s"% g_map); print ("list value:%s"% g_ls); print ("\ n\ n"); if "_ _ main__" = = _ _ name__: PrintVal ("The orgin vlaue"); FixInt (); FixString (); FixMap (); FixList (); PrintVal ("print all bGlobal = False vlaue") FixInt (True); FixString (True); FixMap (True); FixList (True); PrintVal ("print all bGlobal = True vlaue")

Results:

= The orgin vlaue = int value:0string value:aaaamap value: {'aaa':' 111, 'bbb':' 222, 'ccc':' 333, 'ddd':' 444'} list value: ['aaa':', 'baked,' c'] g_nVal src:0g_nVal dst:1==== print all bGlobal = int value:1string value:aaaabmap value: {'aaa':' aaa__aaaab', 'bbb':' bbb__aaaab' 'ccc':' ccc__aaaab', 'ddd':' ddd__aaaab'} list value: ['aaa':', 'baked,' cased,'1'] g_nVal src:1g_nVal dst:2==== print all bGlobal = True value = int value:2string value:aaaabbmap value: {'aaa':' aaa__aaaabb', 'bbb':' bbb__aaaabb', 'ccc':' ccc__aaaabb' 'ddd':' ddd__aaaabb'} list value: ['await,' baked, 'cased,' 1percent,'1'] that's all about how to create and modify python global. I hope the above content can be of some help to you and learn more knowledge. If you think the article is good, you can share it for more people to see.

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