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    If statement syntax error

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    • OkieWolf
      OkieWolf last edited by OkieWolf

      The below works. But the if statement isn’t catching the blank textfield. If one is blank it errors trying to create sidea or sideb (whichever is blank). Also, it never gets to the else statement.

      def button3_tapped(sender):
	if (v['textfield3'].text) is not None and (v['textfield4'].text) is not None:
		sidea = float(v['textfield3'].text)
		sideb = float(v['textfield4'].text)
		sidec = sidea + sideb
		v['textfield5'].text = 'sidec = ' + str(sidec)
	else:
		v['textfield5'].text = 'ENTER ALL REQUIRED FIELDS' `
      mcriley821 1 Reply Last reply Reply Quote 0
      • mcriley821
        mcriley821 @OkieWolf last edited by

        @OkieWolf

        def button3_tapped(sender):
    if v['textfield3'].text and v['textfield4'].text:
        try:
                sidea = float(v['textfield3'].text)
                sideb = float(v['textfield4'].text)
        except ValueError:
                v['textfield5'].text = 'ENTER ALL REQUIRED FIELDS CORRECTLY'
        else:
                sidec = sidea + sideb
                v['textfield5'].text = f'sidec = {sidec}'
        1 Reply Last reply Reply Quote 0
        • OkieWolf
          OkieWolf last edited by

          Figured it out. See below....

          def button3_tapped(sender):
	if (v['textfield3'].text)!="" and (v['textfield4'].text)!="":
		sidea = float(v['textfield3'].text)
		sideb = float(v['textfield4'].text)
		sidec = sidea + sideb
		v['textfield5'].text = 'sidec = ' + str(sidec)
	else:
		v['textfield5'].text = 'ENTER ALL REQUIRED FIELDS' ```
          mcriley821 1 Reply Last reply Reply Quote 0
          • mcriley821
            mcriley821 @OkieWolf last edited by

            @OkieWolf this will throw an exception if the string can’t convert to a float. If you suspect that won’t happen, your code is fine. Otherwise my previous code would be more robust

            1 Reply Last reply Reply Quote 1
            • OkieWolf
              OkieWolf last edited by

              New issue.
              I want to change the background color of the textfield to red if one of the fields is blank. Below is what I’ve done. It doesn’t error but it doesn’t change the color either. I also tried ‘red’ instead of the hex code but that doesn’t work either.

              def button3_tapped(sender):
	if (v['textfield3'].text)!="" and (v['textfield4'].text)!="":
		sidea = float(v['textfield3'].text)
		sideb = float(v['textfield4'].text)
		sidec = sidea + sideb
		v['textfield5'].text = 'sidec = ' + str(sidec)
	else:
		v['textfield5'].background_color = 'fffffff8'
		v['textfield5'].text = 'ENTER ALL FIELDS' ```
              mcriley821 1 Reply Last reply Reply Quote 0
              • mcriley821
                mcriley821 @OkieWolf last edited by mcriley821

                @OkieWolf
                To specify hex you have to have a # in front

                red = '#ff0000'

                The current hex value you have is mostly white. It’s also too long. 'red' should work too

                OkieWolf 1 Reply Last reply Reply Quote 0
                • OkieWolf
                  OkieWolf @mcriley821 last edited by

                  @mcriley821
                  Still doesn’t change

                  mcriley821 1 Reply Last reply Reply Quote 0
                  • mcriley821
                    mcriley821 @OkieWolf last edited by

                    @OkieWolf then it’s not making it to the else statement. What are you inputting to the textfields? Maybe one of them is white space?

                    OkieWolf 1 Reply Last reply Reply Quote 0
                    • OkieWolf
                      OkieWolf @mcriley821 last edited by

                      @mcriley821
                      It’s getting to the else statement because it’s inputting the text “Enter All Fields”. It just won’t change the color.

                      cvp mikael 2 Replies Last reply Reply Quote 0
                      • mcriley821
                        mcriley821 last edited by

                        @OkieWolf

                        Scratch that, sorry. I was thinking of a label. A textField doesn’t really have a background. It’s background is behind the white layer. What you could do instead is make a red border.

                        If you really want the whole thing red, I can write a small bit of code with objc_util

                        1 Reply Last reply Reply Quote 0
                        • cvp
                          cvp @OkieWolf last edited by

                          @OkieWolf already done here

                          1 Reply Last reply Reply Quote 1
                          • mikael
                            mikael @OkieWolf last edited by

                            @OkieWolf, you hit one of known quirks. You can set bordered to False, after which background_color works. Or if that appearance does not work for you, @cvp’s solution can be turned into a helper function that you can call with just 'red':

                            def textfield_background(tf, color):
    import objc_util
    tfo = tf.objc_instance.textField()
    tfo.backgroundColor = objc_util.UIColor.colorWithRed_green_blue_alpha_(
        *ui.parse_color(color))
                            OkieWolf 1 Reply Last reply Reply Quote 0
                            • OkieWolf
                              OkieWolf last edited by

                              What about text color? Can I change the textfield text color to red?

                              cvp 1 Reply Last reply Reply Quote 0
                              • cvp
                                cvp @OkieWolf last edited by

                                @OkieWolf .text_color = 'red'

                                1 Reply Last reply Reply Quote 0
                                • OkieWolf
                                  OkieWolf @mikael last edited by

                                  This post is deleted!
                                  1 Reply Last reply Reply Quote 0
                                  • OkieWolf
                                    OkieWolf last edited by OkieWolf

                                    Here’s the completed button using the Pythagorean Theorem to calculate. It looks to see which of the three textfields is blank then calculates what it should be based on the input of the other two.

                                    def button3_tapped(sender):
	if (v['textfield3'].text)!="" and (v['textfield4'].text)!="":
		hyp = float(v['textfield3'].text)
		sht = float(v['textfield4'].text)
		hyp = pow(hyp,2)
		sht = pow(sht,2)
		lng = math.sqrt(hyp - sht)
		v['textfield5'].text_color = 'green'
		v['textfield5'].text = str(lng)
	elif (v['textfield4'].text)!="" and (v['textfield5'].text)!="":
		sht = float(v['textfield4'].text)
		lng = float(v['textfield5'].text)
		sht = pow(sht,2)
		lng = pow(lng,2)
		hyp = math.sqrt(sht + lng)
		v['textfield3'].text_color = 'green'
		v['textfield3'].text = str(hyp)
	elif (v['textfield3'].text)!="" and (v['textfield5'].text)!="":
		hyp = float(v['textfield3'].text)
		lng = float(v['textfield5'].text)
		hyp = pow(hyp,2)
		lng = pow(lng,2)
		sht = math.sqrt(hyp - lng)
		v['textfield4'].text_color = 'green'
		v['textfield4'].text = str(sht)
	else:
		v['textfield5'].text_color = 'red'
		v['textfield5'].text = 'ENTER ALL FIELDS' ```
                                    1 Reply Last reply Reply Quote 1
                                    • ccc
                                      ccc last edited by ccc

                                      The logic is easier to follow if field names describe their content.

                                      def button3_tapped(sender):
    hypotenuse = float(v['hypotenuse'].text or 0)
    short = float(v['short'].text or 0)
    long = float(v['long'].text or 0)
    if len([x for x in (hypotenuse, short, long) if x]) != 2:
        v['long'].text = "Enter floats in 2 fields"
        v['long'].text_color = 'red'
        return
    if hypotenuse:
        if short and not long:
            v['long'].text = str(math.sqrt(hypotenuse ** 2 - short ** 2))
            v['long'].text_color = 'green'
        elif long and not short:
            v['short'].txt = str(math.sqrt(hypotenuse ** 2 - long ** 2))
            v['short'].text_color = 'green'
    else:
        v['hypotenuse'].text = str(math.sqrt(short ** 2 + long ** 2))
        v['hypotenuse'].text_color = 'green'
                                      OkieWolf 1 Reply Last reply Reply Quote 0
                                      • OkieWolf
                                        OkieWolf @ccc last edited by OkieWolf

                                        @ccc
                                        Could you please explain how this works in more detail?
                                        I realize you’ve renamed textfields but I’m not exactly understanding how the code is working. I’m mainly not understanding what’s happening with the or 0 and then the if len([x for x in (hypotenuse, short, long) if x]) != 2

                                        hypotenuse = float(v['hypotenuse'].text or 0)
    short = float(v['short'].text or 0)
    long = float(v['long'].text or 0)
    if len([x for x in (hypotenuse, short, long) if x]) != 2: ```
                                        mcriley821 1 Reply Last reply Reply Quote 0
                                        • mcriley821
                                          mcriley821 @OkieWolf last edited by ccc

                                          @OkieWolf

                                          hypotenuse = float(v['hypotenuse'].text or 0)
    short = float(v['short'].text or 0)
    long = float(v['long'].text or 0)
    if len([x for x in (hypotenuse, short, long) if x]) != 2: ```

                                          v['short'].text or 0 will choose 0 if the text is "". You won’t hit an exception for a blank textfield. You will get an error if the text is alphabetical though.

                                          (hypotenuse,short,long) is a tuple and [x for x in (hypotenuse,short,long) if x] is a list comprehension that steps through the tuple
                                          and makes a list of the values that exist. Then if the length of that list isn’t 2, then you don’t have a correct input

                                          1 Reply Last reply Reply Quote 0
                                          • OkieWolf
                                            OkieWolf last edited by

                                            I need to probably rewrite the whole program because I’ve added more error trapping and a fourth textfield. It has increased complexity quite a bit, at least for me. It now cycles through all four textfields, find any two valid fields, decides whether to use Pythagorean Theorem or plain trig, and checks all for errors. One error in particular is that it is possible with the answers to have the short side of the triangle be longer than the long side. Obviously this can never happen so it’s now trapped and alerts the user.
                                            Below is what I now have. I realize my code is a longer than it needs to be and fairly cumbersome at this point but I’m just learning Python and intend to try to rewrite it in a better and more efficient way.

                                            def button3_tapped(sender):
	if (v['textfield3'].text)!="" and (v['textfield4'].text)!="":
		v['label7'].background_color = 'white'
		v['label7'].text_color = 'white'
		v['label7'].text = ''
		hyp = float(v['textfield3'].text)
		sht = float(v['textfield4'].text)
		hypa = hyp
		shta = sht
		hyp = pow(hyp,2)
		sht = pow(sht,2)
		lng = math.sqrt(hyp - sht)
		lnga = lng
		ang = math.asin(shta/hypa)
		ang = math.degrees(ang)
		v['textfield5'].text_color = 'green'
		v['textfield5'].text = str(lng)
		v['textfield6'].text_color = 'green'
		v['textfield6'].text = str(ang)
		shtb = float(v['textfield4'].text)
		lngb = float(v['textfield5'].text)
		if shtb > lngb:
			v['label7'].background_color = 'red'
			v['label7'].text_color = 'white'
			v['label7'].text = 'ERROR. Short side cannot be longer than long side.'
	elif (v['textfield4'].text)!="" and (v['textfield5'].text)!="":
		v['label7'].background_color = 'white'
		v['label7'].text_color = 'white'
		v['label7'].text = ''
		sht = float(v['textfield4'].text)
		shta = sht
		lng = float(v['textfield5'].text)
		lnga = lng
		sht = pow(sht,2)
		lng = pow(lng,2)
		hyp = math.sqrt(sht + lng)
		hypa = hyp
		ang = math.asin(shta/hypa)
		ang = math.degrees(ang)
		v['textfield3'].text_color = 'green'
		v['textfield3'].text = str(hyp)
		v['textfield6'].text_color = 'green'
		v['textfield6'].text = str(ang)
		shtb = float(v['textfield4'].text)
		lngb = float(v['textfield5'].text)
		if shtb > lngb:
			v['label7'].background_color = 'red'
			v['label7'].text_color = 'white'
			v['label7'].text = 'ERROR. Short side cannot be longer than long side.'
	elif (v['textfield3'].text)!="" and (v['textfield5'].text)!="":
		v['label7'].background_color = 'white'
		v['label7'].text_color = 'white'
		v['label7'].text = ''
		hyp = float(v['textfield3'].text)
		hypa = hyp
		lng = float(v['textfield5'].text)
		lnga = lng
		hyp = pow(hyp,2)
		lng = pow(lng,2)
		sht = math.sqrt(hyp - lng)
		shta = sht
		ang = math.asin(shta/hypa)
		ang = math.degrees(ang)
		v['textfield4'].text_color = 'green'
		v['textfield4'].text = str(sht)
		v['textfield6'].text_color = 'green'
		v['textfield6'].text = str(ang)
		shtb = float(v['textfield4'].text)
		lngb = float(v['textfield5'].text)
		if shtb > lngb:
			v['label7'].background_color = 'red'
			v['label7'].text_color = 'white'
			v['label7'].text = 'ERROR. Short side cannot be longer than long side.'
	elif (v['textfield3'].text)!="" and (v['textfield6'].text)!="":
		v['label7'].background_color = 'white'
		v['label7'].text_color = 'white'
		v['label7'].text = ''
		hyp = float(v['textfield3'].text)
		ang = float(v['textfield6'].text)
		ang = math.radians(ang)
		hypa = hyp
		sht = hyp * math.sin(ang)
		shta = sht
		hypc = pow(hyp,2)
		shtc = pow(sht,2)
		lng = math.sqrt(hypc - shtc)
		lnga = lng
		v['textfield5'].text_color = 'green'
		v['textfield5'].text = str(lng)
		v['textfield4'].text_color = 'green'
		v['textfield4'].text = str(sht)
		shtb = float(v['textfield4'].text)
		lngb = float(v['textfield5'].text)
		if shtb > lngb:
			v['label7'].background_color = 'red'
			v['label7'].text_color = 'white'
			v['label7'].text = 'ERROR. Short side cannot be longer than long side.'
	elif (v['textfield4'].text)!="" and (v['textfield6'].text)!="":
		v['label7'].background_color = 'white'
		v['label7'].text_color = 'white'
		v['label7'].text = ''
		sht = float(v['textfield4'].text)
		ang = float(v['textfield6'].text)
		ang = math.radians(ang)
		shta = sht
		hyp = sht / math.sin(ang)
		hypa = hyp
		hypc = pow(hyp,2)
		shtc = pow(sht,2)
		lng = math.sqrt(hypc - shtc)
		shta = sht
		v['textfield5'].text_color = 'green'
		v['textfield5'].text = str(lng)
		v['textfield3'].text_color = 'green'
		v['textfield3'].text = str(hyp)
		shtb = float(v['textfield4'].text)
		lngb = float(v['textfield5'].text)
		if shtb > lngb:
			v['label7'].background_color = 'red'
			v['label7'].text_color = 'white'
			v['label7'].text = 'ERROR. Short side cannot be longer than long side.'
	elif (v['textfield5'].text)!="" and (v['textfield6'].text)!="":
		v['label7'].background_color = 'white'
		v['label7'].text_color = 'white'
		v['label7'].text = ''
		lng = float(v['textfield5'].text)
		ang = float(v['textfield6'].text)
		ang = math.radians(ang)
		lnga = lng
		hyp = lng / math.cos(ang)
		hypa = hyp
		hypc = pow(hyp,2)
		lngc = pow(lng,2)
		sht = math.sqrt(hypc - lngc)
		shta = sht
		v['textfield4'].text_color = 'green'
		v['textfield4'].text = str(sht)
		v['textfield3'].text_color = 'green'
		v['textfield3'].text = str(hyp)
		shtb = float(v['textfield4'].text)
		lngb = float(v['textfield5'].text)
		if shtb > lngb:
			v['label7'].background_color = 'red'
			v['label7'].text_color = 'white'
			v['label7'].text = 'ERROR. Short side cannot be longer than long side.'
	else:
		v['label7'].background_color = 'red'
		v['label7'].text_color = 'white'
		v['label7'].text = 'ERROR' ```
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