1)在子程序中對全局變量的操作,比如
val=9
def test(flag):
if flag:
val = 1
else:
print 'Error'
return val
test(0)
錯誤提示:UnboundLocalError: local variable 'val' referenced before assignment解決方法:用global關鍵字來進行說明該變量是全局變量
val=9
def test(flag):
global val
if flag:
val = 1
else:
print 'test'
return val
test(0)
2)局部變量,但仍然報出unboundLocal Error問題
比如:
def test(flag):
if (a):
bbb = aaa
elif(b):
bbb2 = aaa2
print(bbb2)
錯誤提示:UnboundLocalError: local variable 'bbb2' referenced before assignment
報錯的原因是python認爲bbb2不一定能被賦值。
解決方案:先對bbb2賦值
def test(flag):
bbb2=0
if (a):
bbb = aaa
elif(b):
bbb2 = aaa2
print(bbb2)