TypeError: can't convert 'str' object to str implicitly

Reply to TypeError: can't convert 'str' object to str implicitly on Thu, 11 May 2017 15:24:28 GMT

Andrea Filippini — Thu, 11 May 2017 15:24:28 GMT

What does exactly mean this error? I'm confused

Reply to TypeError: can't convert 'str' object to str implicitly on Thu, 11 May 2017 16:41:17 GMT

bucknall — Thu, 11 May 2017 16:41:17 GMT

Hi @Andrea-Filippini,

Could you please share the code that caused this error?

Thanks,

Alex

Reply to TypeError: can't convert 'str' object to str implicitly on Fri, 19 May 2017 13:23:14 GMT

Andrea Filippini — Fri, 19 May 2017 13:23:14 GMT

@bucknall My question is not really relative to a piece of code in particular, but here's an example:

s = b'foo|bar'
sp = s.split('|')

while this

s = b'foo|bar'
sp = str(s).split('|')

and this works

s = b'foo|bar'
sp = s.decode('utf-8').split('|')

Please explain the difference

Reply to TypeError: can't convert 'str' object to str implicitly on Sat, 20 May 2017 15:28:13 GMT

PiAir — Sat, 20 May 2017 15:28:13 GMT

@Andrea-Filippini said in TypeError: can't convert 'str' object to str implicitly:

s = b'foo|bar'

The variable s that you create is of type byte, while split() is intended to be used on variables of type str (string).
The other two code fragments that you provide first convert the byte to a string before split() is applied.
Take a look at this:

>>> s = b'foo|bar'
>>> type(s)

>>> s2 = str(s)
>>> type(s2)

>>> s3= s.decode('utf-8')
>>> type (s3)

the type() function gives you the type of an object/variable. You can see that .decode() and str() causes the byte object to be converted explicitly to a string (instead of implicitly expecting that that is being done for you by using split() on a byte object).

Hope this explains it?

Reply to TypeError: can't convert 'str' object to str implicitly on Sat, 20 May 2017 15:36:27 GMT

robert-hh — Sat, 20 May 2017 15:36:27 GMT

@Andrea-Filippini
sp = s.split(b'|')
works too. The difference is, that in the error case you mix string and bytes objects. The conversion you apply in your working examples you show convert the bytes object to string, and the split with a string works.
P.S.: I would say that the error message is misleading.

Reply to TypeError: can't convert 'str' object to str implicitly on Sat, 20 May 2017 15:40:16 GMT

PiAir — Sat, 20 May 2017 15:40:16 GMT

@robert-hh it works but gives a different result:

>>> sp = s.split(b'|')
>>> type(sp)

Reply to TypeError: can't convert 'str' object to str implicitly on Sat, 20 May 2017 15:54:15 GMT

robert-hh — Sat, 20 May 2017 15:54:15 GMT

@PiAir split() always returns a list. You'll see a difference with type(sp[0]).

Reply to TypeError: can't convert 'str' object to str implicitly on Sat, 20 May 2017 15:58:08 GMT

PiAir — Sat, 20 May 2017 15:58:08 GMT

@robert-hh my bad, you're right

>>> type(s.split(b'|')[0])

>>> type(str(s).split('|')[0])

Reply to TypeError: can't convert 'str' object to str implicitly on Tue, 17 Mar 2020 07:47:01 GMT

germyrinn — Tue, 17 Mar 2020 07:47:01 GMT

Python makes a clear distinction between bytes and strings . Bytes objects contain raw data — a sequence of octets — whereas strings are Unicode sequences . Conversion between these two types is explicit: you encode a string to get bytes, specifying an encoding (which defaults to UTF-8); and you decode bytes to get a string. Clients of these functions should be aware that such conversions may fail, and should consider how failures are handled.

We can convert bytes to string using bytes class decode() instance method, So you need to decode the bytes object to produce a string. In Python 3 , the default encoding is "utf-8" , so you can use directly:

b"python byte to string".decode("utf-8")