在Python中声明文件句柄

您不需要声明变量,Python使用函数范围。中声明的变量 try 如果分配被执行而没有任何异常,则块将在之后自动可用:

案例1:无例外

try:
    inputFile = open( sys.argv[0] )
except IOError as e:
    print "ERROR: Could not open " + sys.argv[0]
# inputFile is opened file

案例2:例外

try:
    inputFile = open( sys.argv[0] )
except IOError as e:
    print "ERROR: Could not open " + sys.argv[0]
# inputFile is not defined

使用 with .

try:
    with open(sys.argv[0]) as f:
        # operate on the file
except IOError as e:
    # handle the exception