CODEWITHSUNDEEP
pythonmysqlstringtypesbyte
icecreamscoop
icecreamscoop

Reputation: 71

How to insert bytes into a Python string

I need to insert bytes into a string because I'm using the marshal Python module to serialize my functions (because I'll insert them into a database later). I need some way to pass the bytes through the MySQL query because whenever I try I get:

Query += "'" + value + "'"

TypeError: Can't convert 'bytes' object to str implicitly

So, I need to know what to do in order to pass it in my query variable without errors.

EDIT: since someone marked it as a duplicate, I can't simply decode it to utf-8 because it contains characters that utf8 doesn't support

Upvotes: 1

Views: 3206

Answers (2)

Serge Ballesta
Serge Ballesta

Reputation: 148890

If you want to convert any bytes to a string, you should never use utf8 but a charset that supports the 256 bytes such as latin1 or iso-8859-1.

Here is a little test:

a = bytes(range(256))
b = a.decode('latin1')
c = b.encode('latin1')
c == a

gives True

So for your use case, you could use: Query += "'" + value.decode('latin1') + "'"

For references, a gives

b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff'

and b gives:

'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0¡¢£¤¥¦§¨©ª«¬\xad®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ'

Upvotes: 1

Chad Kennedy
Chad Kennedy

Reputation: 1736

Change

Query += " VALUES("

to

Query += " VALUES(%s)"

and drop the rest of the lines up to the Execute. When you call execute, do it like this:

self.Execute(Query, (*values))

This uses the MySQL module to do the formatting, instead of Python. This is necessary for binary data.

Upvotes: 0

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