筆記-python異常資訊輸出
筆記-python異常資訊輸出
1. 異常資訊輸出
python異常捕獲使用try-except-else-finally語句;
在except 語句中可以使用except as e,然後通過e得到異常資訊;
- str(e): # 返回字串型別,只給出異常資訊,不包括異常資訊的型別,如I/O的異常資訊。
division by zero
- repr(e): #給出較全的異常資訊,包括異常資訊的型別
ZeroDivisionError('division by zero',)
- e.message #資訊最為豐富,一般情況下使用這個選項就足夠了
- traceback# 獲取資訊最全
2. traceback
This module provides a standard interface to extract, format and print stack traces of Python programs. It exactly mimics the behavior of the Python interpreter when it prints a stack trace. This is useful when you want to print stack traces under program control, such as in a “wrapper” around the interpreter.
The module uses traceback objects — this is the object type that is stored in the sys.last_traceback variable and returned as the third item from sys.exc_info().
比較常用的方法有:
print_exception(etype, value, tb [ ,limit [,file ] ])
print_exc([limit [ , file ] ]) # 它是一個print_exception的簡寫,列印資訊
format_exc() # 與print_exc類似,但它返回一個字串,而不是列印
案例程式碼:
import traceback
import sys
class Myex_ValueError(Exception):
"""
my exception
"""
def __init__(self, msg):
self.message = msg
try:
a = 5
b = 5/0
raise Myex_ValueError('error')
except Exception as e:
#print(e)
#print(str(e))
#print(repr(e))
#print(e.__class__)
#print(e.message)
#traceback.print_exc()
print(traceback.format_exc())
#traceback.print_stack()
3. sys
上面提到了traceback會生成traceback 物件,而這個物件可以通過sys.exc_info()得到。
sys.exc_info()的返回值是一個tuple, (type, value/message, traceback)
這裡的type ---- 異常的型別
value/message ---- 異常的資訊或者引數
traceback ---- 包含呼叫棧資訊的物件。