Can't convert 'int' object to str implicitly

[theMusicMan]

I have a BME280 sensor connected and returning values as expected, which I am then able to upload to adafruit.

However, the BME280's pressure reading requires some local calibration, and I would simply like to add 3 to its returned pressure value. The code that gets the values from the sensor and prints them all to the console is...

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        # Grab the latest enviromental values and print to the console (if open)
        envi = bme.values
        print(envi)

and the code that specifically pushes the pressure value up to adafruit is shown here;

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           c.publish(conf['user']+"/feeds/pres", envi[1])

When I simply type;

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           c.publish(conf['user']+"/feeds/pres", envi[1] + 3)

... to the code, I get the above error as I gather I am trying to add an integer to a character, or something such as that!

So, can anyone advise please how I would go about simply adding 3 (or any value) to the env[1] variable please? Many thanks.

[Andyroo]

Hi,

In python you can find the type of a variable by using:

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print(type(variablename))

In this case assuming it is a string / character you can use the int function for integers:

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c.publish(conf['user']+"/feeds/pres", int(envi[1]) + 3)

Note that above does not round up - it goes to the integer closest to zero (both pos and neg).

If you want to keep the decimal places then use the float function:

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c.publish(conf['user']+"/feeds/pres", float(envi[1]) + 3)

If you want to round to a given number of places then use the round function:

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print(round(3.145,2))

will give 3.15 where as:

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print(round(3.145,1))

will give 3.1

Sorry for the waffle but it may help others long term

[theMusicMan]

Hi,
Sorry for the waffle but it may help others long term

You're kidding me yeah...? waffle...? Not a chance... This is a superb answer, thank you so much.

[Andyroo]

Hi,
Sorry for the waffle but it may help others long term

You're kidding me yeah...? waffle...? Not a chance... This is a superb answer, thank you so much.

Ahh but does it work?

[theMusicMan]

Hi,
Sorry for the waffle but it may help others long term

You're kidding me yeah...? waffle...? Not a chance... This is a superb answer, thank you so much.

Ahh but does it work?

Alas not! The result of the type is class = tuple

Still an excellently informed reply

[Andyroo]

OK - I would expect. That as it’s basically an array of values being returned. Did you try int(envi[1]) or just int(envi)?

Do you have a link to the board and the software library you are using?

If all fails (Pythons reasonably new to me) ave you seen this library https://github.com/adafruit/Adafruit_Python_BME280. Though deprecated it may still work and let you add the fiddle factor.

My sensor is still in its bag and my play Pi Zero is tied up in a WLAN test at the mo so I’m a bit blind (and daft)...

[theMusicMan]

OK - I would expect. That as it’s basically an array of values being returned. Did you try int(envi[1]) or just int(envi)?

Do you have a link to the board and the software library you are using?

If all fails (Pythons reasonably new to me) ave you seen this library https://github.com/adafruit/Adafruit_Python_BME280. Though deprecated it may still work and let you add the fiddle factor.

My sensor is still in its bag and my play Pi Zero is tied up in a WLAN test at the mo so I’m a bit blind (and daft)...

I tried assign a new variable ...

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p = int(envi[1]) + 3

And I had an error returned which is; invalid syntax for integer with base 10

I am guessing this is because envi[1] is a string that ends with characters... it is actually 1029.34hPa

So what I need to be able to do is to convert just the number part of that string to an integer, add 3 to it, then convert it back to a string to parse to the MQTT server.

[pcmanbob]

So your value is actually a float value because it has a decimal , int would remove the decimal, so 1029.34 would become 1029.

so to do what you want assuming you want the string to read the same but with just 3 added to the value you need this simple bit of code.

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p = "1029.34hpa"			 # your string replace with p = envi[1]
string = p.split("h") 			# split the number from the text at h
value = float(string[0]) + 3.0		 #convert number in string to float value and add 3
p = str(value) + "hPa"			 # convert back to string and add text back on end of new value
print(p)  				# just here to show the result you can delete this line.

If you let p = envi[1] as suggested you can just copy the code in you your program and p will equal the result you want at the end.

[theMusicMan]

So your value is actually a float value because it has a decimal , int would remove the decimal, so 1029.34 would become 1029.

so to do what you want assuming you want the string to read the same but with just 3 added to the value you need this simple bit of code.

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p = "1029.34hpa"			 # your string replace with p = envi[1]
string = p.split("h") 			# split the number from the text at h
value = float(string[0]) + 3.0		 #convert number in string to float value and add 3
p = str(value) + "hPa"			 # convert back to string and add text back on end of new value
print(p)  				# just here to show the result you can delete this line.

If you let p = envi[1] as suggested you can just copy the code in you your program and p will equal the result you want at the end.

Worked a treat, many thanks Bob

[lovelmark]

A TypeError can occur if the type of an object is not what the Python interpreter expected to see. This error is a common mistake made by beginning developers is to use the '+' operator between values of incompatible types. This error message Can't convert 'int' object to str implicitly is clear, when concatenating strings with integers - you can't directly stick together a string and an integer. So, in order to resolve this problem, you have to explicitly parse the integer to a string by the str() built-in function .