In this tutorial, you\u2019ll learn various techniques to catch multiple exceptions with Python. To begin with, you\u2019ll review Python\u2019s exception handling<\/strong> mechanism before diving deeper and learning how to identify what you\u2019ve caught, sometimes ignore what you\u2019ve caught, and even catch lots of exceptions.<\/p>\n Python raises an exception<\/a> when your code encounters an occasional but not unexpected error. For example, this will occur if you try to read a missing file. Because you\u2019re aware that such exceptions may occur, you should write code to deal with, or handle<\/strong>, them. In contrast, a bug<\/strong> happens when your code does something illogical, like a miscalculation. Bugs should be fixed, not handled. This is why debugging your code<\/a> is important.<\/p>\n When your Python program encounters an error and raises an exception, your code will probably crash, but not before providing a message within a traceback<\/a> indicating what the problem is:<\/p>\n Here, you\u2019ve tried to divide a number<\/a> by a string<\/a>. Python can\u2019t do this, so it raises a To allow you to take action when an error occurs, you implement exception handling<\/a> by writing code to catch<\/strong> and deal with exceptions. Better this than your code crashing and scaring your user. To handle exceptions, you use the Most The One or more To learn how this works, you write a The code that you\u2019re monitoring asks the user to enter both numbers and then prints the division. You\u2019ll cause a Having written the above code, you then test each of the control flows. To do this, you first provide perfectly valid data, then provide a The good news is that your code never crashes. This is because your code has successfully handled the exceptions.<\/p>\n First, you provided acceptable data. When you look at the output, you can see that the program flows only through You then cause a In your final test run, you try to divide by After the error handling is complete, your program\u2019s flow would usually continue with any code beyond the As an exercise, you might like to try entering a string as the first input and a number as the second. Can you predict what will happen before you try it out? <\/p>\n Note:<\/strong> Your code catches only Up to this point, you\u2019ve reviewed how to catch exceptions individually using the Get Your Code:<\/strong> Click here to download the sample code<\/a> that shows you how to catch multiple exceptions in Python.<\/p>\n<\/div>\n Catching individual exceptions in separate Suppose you now like the idea of your earlier code being able to handle both exceptions in a single line. To do this, you decide to rewrite your code as follows:<\/p>\n<\/div>\n [ Improve Your Python With ? Python Tricks ? \u2013 Get a short & sweet Python Trick delivered to your inbox every couple of days. >> Click here to learn more and see examples<\/a> ]<\/em><\/p>\n\n In this how-to tutorial, you’ll learn different ways of catching multiple Python exceptions. You’ll review the standard way of using a tuple in the except clause, but also expand your knowledge by exploring some other techniques, such as suppressing exceptions and using exception groups.<\/p>\n<\/div>","protected":false},"author":2055,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"How to Catch Multiple Exceptions in Python - ITTeacherITFreelance.hk","description":"In this how-to tutorial, you'll learn different ways of catching multiple Python exceptions. You'll review the standard way of using a tuple in the except claus"},"footnotes":""},"categories":[10700],"tags":[],"_links":{"self":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/329494"}],"collection":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/users\/2055"}],"replies":[{"embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/comments?post=329494"}],"version-history":[{"count":1,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/329494\/revisions"}],"predecessor-version":[{"id":329495,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/329494\/revisions\/329495"}],"wp:attachment":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/media?parent=329494"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/categories?post=329494"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/tags?post=329494"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/span>>>> <\/span>12<\/span> \/<\/span> \"five\"<\/span>\nTraceback (most recent call last):<\/span>\n <\/span>...<\/span>\nTypeError<\/span>: unsupported operand type(s) for \/: 'int' and 'str'<\/span>\n<\/code><\/pre>\n<\/div>\nTypeError<\/code><\/a> exception. It then shows a traceback reminding you that the division operator doesn\u2019t work with strings.<\/p>\ntry<\/code><\/a> statement. This allows you to monitor code for exceptions and take action should they occur.<\/p>\ntry<\/code> statements use try<\/code> \u2026 except<\/code><\/a> blocks as follows:<\/p>\n\n
try<\/code> block contains the code that you wish to monitor for exceptions. Any exceptions raised within try<\/code> will be eligible for handling.<\/p>\n<\/li>\nexcept<\/code> blocks then follow try<\/code>. These are where you define the code that will run when exceptions occur. In your code, any raised exceptions trigger the associated except<\/code> clause. Note that where you have multiple except<\/code> clauses, your program will run only the first one<\/em> that triggers and then ignore the rest.<\/p>\n<\/li>\n<\/ul>\ntry<\/code> block to monitor three lines of code. You include two except<\/code> blocks, one each for ValueError<\/code><\/a> and ZeroDivisionError<\/code><\/a> exceptions, to handle them should they occur:<\/p>\n<\/span># handler_statement.py<\/span>\n\ntry<\/span>:<\/span>\n first<\/span> =<\/span> float<\/span>(<\/span>input<\/span>(<\/span>\"What is your first number? \"<\/span>))<\/span>\n second<\/span> =<\/span> float<\/span>(<\/span>input<\/span>(<\/span>\"What is your second number? \"<\/span>))<\/span>\n print<\/span>(<\/span>f<\/span>\"<\/span>{<\/span>first<\/span>}<\/span> divided by <\/span>{<\/span>second<\/span>}<\/span> is <\/span>{<\/span>first<\/span> <\/span>\/<\/span> <\/span>second<\/span>}<\/span>\"<\/span>)<\/span>\nexcept<\/span> ValueError<\/span>:<\/span>\n print<\/span>(<\/span>\"You must enter a number\"<\/span>)<\/span>\nexcept<\/span> ZeroDivisionError<\/span>:<\/span>\n print<\/span>(<\/span>\"You can't divide by zero\"<\/span>)<\/span>\n<\/code><\/pre>\n<\/div>\nValueError<\/code> if you don\u2019t enter a number in the first two lines of code. When the float()<\/code> function tries to convert your input into a float<\/code>, a ValueError<\/code> occurs if this isn\u2019t possible. A ZeroDivisionError<\/code> occurs if you enter 0<\/code> as the second number. When the print()<\/code> function attempts to divide by zero, you get a ZeroDivisionError<\/code>. <\/p>\nstring<\/code> for the second number, and finally provide a 0<\/code> for the second number: <\/p>\n<\/span>$ <\/span>python <\/span>handler_statement.py\nWhat is your first number? 10<\/span>\nWhat is your second number? 5<\/span>\n10.0 divided by 5.0 is 2.0<\/span>\n\n$ <\/span>python <\/span>handler_statement.py\nWhat is your first number? 10<\/span>\nWhat is your second number? \"five\"<\/span>\nYou must enter a number<\/span>\n\n$ <\/span>python <\/span>handler_statement.py\nWhat is your first number? 10<\/span>\nWhat is your second number? 0<\/span>\nYou can't divide by zero<\/span>\n<\/code><\/pre>\n<\/div>\ntry<\/code>. You haven\u2019t invoked any of the except<\/code> clauses because Python hasn\u2019t raised any exceptions.<\/p>\nValueError<\/code> by entering a string. This happens because the float()<\/code><\/a> function can\u2019t convert your \"five\"<\/code> into a float<\/code>. Your program flow now becomes try<\/code> then except ValueError<\/code>. Despite raising a ValueError<\/code>, your code has handled it gracefully. Your users will no longer experience a worrying crash.<\/p>\n0<\/code>. This time, you cause a ZeroDivisionError<\/code> because Python doesn\u2019t like your enthusiasm for Riemann spheres and infinity<\/a>. This time, the program flow is try<\/code> then except ZeroDivisionError<\/code>. Again, your code has handled your exception gracefully. Most of your users will be happy with this, though the mathematicians may be disappointed.<\/p>\ntry<\/code> statement. In this case, there\u2019s none, so the program simply ends. <\/p>\nZeroDivisionError<\/code> or ValueError<\/code> exceptions. Should any others be raised, it\u2019ll crash as before. You could get around this by creating a final except Exception<\/code> clause to catch all other exceptions. However, this is bad practice because you might catch exceptions that you didn\u2019t anticipate. It\u2019s better to catch exceptions explicitly and customize your handling of them.<\/p>\n<\/div>\ntry<\/code> statement. In the remainder of this tutorial, you\u2019ll learn about ways that you can catch multiple exceptions. Time to dive a bit deeper.<\/p>\nHow to Catch One of Several Possible Python Exceptions<\/a><\/h2>\n
except<\/code> clauses is the way to go if you need to perform different handling actions on the different exceptions being caught. If you find that you\u2019re performing the same<\/em> actions in response to different exceptions, then you can produce simpler, more readable code by handling multiple exceptions in a single except<\/code> clause. To do this, you specify the exceptions as a tuple<\/a> within the except<\/code> statement.<\/p>\nRead the full article at https:\/\/realpython.com\/python-catch-multiple-exceptions\/ \u00bb<\/a><\/h2>\n
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