python之全局变量的测试

a2005147

　　结论：python的全局变量：int string， list， dic(map) 如果存在global就能够修改它的值。而不管这个global是否是存在于if中，也不管这个if是否能够执行到。
　　但是，如果没有

if bGlobal:
global g_strVal;

　　int string 将会报错。而list dic(map)是ok的。

#!/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 = ['a', 'b', 'c']
def FixInt(bGlobal = False):
if bGlobal:
global g_nVal;   
g_nVal = g_nVal + 1;
def FixString(bGlobal = False):
if bGlobal:
global g_strVal;
#fix string value
g_strVal = g_strVal + 'b';
def FixMap(bGlobal = False):
if bGlobal:
global g_map;
#fix map value   
g_map['aaa'] = 'aaa__' + g_strVal;
g_map['bbb'] = 'bbb__' + g_strVal;
g_map['ccc'] = 'ccc__' + g_strVal;
g_map['ddd'] = 'ddd__' + g_strVal;
def FixList(bGlobal = False):
if bGlobal:
global g_ls;
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");


　　结果：
　　==== The orgin vlaue =====

int value:0

string value:aaaa

map value:{'aaa': '111', 'bbb': '222', 'ccc': '333', 'ddd': '444'}

list value:['a', 'b', 'c']




g_nVal src:0

g_nVal dst:1

==== print all bGlobal = False value =====

int value:1

string value:aaaab

map value:{'aaa': 'aaa__aaaab', 'bbb': 'bbb__aaaab', 'ccc': 'ccc__aaaab', 'ddd': 'ddd__aaaab'}

list value:['a', 'b', 'c', '1']




g_nVal src:1

g_nVal dst:2

==== print all bGlobal = True value =====

int value:2

string value:aaaabb

map value:{'aaa': 'aaa__aaaabb', 'bbb': 'bbb__aaaabb', 'ccc': 'ccc__aaaabb', 'ddd': 'ddd__aaaabb'}

list value:['a', 'b', 'c', '1', '1']