Here a program used for convert some units, using switch case an functions: The main code: https://github.com/hrglez/TC1017/blob/master/Units Thank you. Have a good day.
Here a program used for convert some units, using switch case an functions: The main code: https://github.com/hrglez/TC1017/blob/master/Units Thank you. Have a good day.
A switch structure is used for determining a case in base of a expression. Its structure is:
switch (expression) {
case statement :
Instructions;
break;
default:
Instructions;
break;
This works by using the expression given to determine the case that should be executed. For instance if the expression is 1, the set of instructions that will be executed are the ones found in case 1. In case of having different expressions intended to trigger the same set of instructions it could be done by typing them in series:
case 1: case 2: …. case n:
Instructions;
break;
The break statement is important since it stops the flow of the switch and avoids that other set of instructions are executed. Another characteristic is the default statement, that is the one executed if the expression given is not found in the cases.
Here’s an image of the switch case in use and its outputs:
Thanks for watching, hope this allowed you to understand this concept.
Hey today we are going to learn how to use “elif” with a conditional : #Mastery17
Hey today we are going to learn how to use “elif” with a conditional : #Mastery17
Use of “elif” with a conditional Nesting of conditional statements
Use of “elif” with a conditional Nesting of conditional statements
The elif is a conditional used to expand options of a normal conditional of If-Else. It´s very useful when you want to check different conditions at once but at the same time you want to save time at writing the code. Lets see an example, first a program without elif:
x = input(“¿What do you want to do next?”)
if x == “exit”:
#close the program
else:
if x == “pay”:
#go to the pay window
else:
if x == “back”:
#move to the previous window
else:
if x == “next”:
#move to the next window
else:
if x == “add”:
#add the item to the shopping list
else:
print (“please write exit, pay, back, next or add”)
This program is a cheap and lazy representation of an online store. It receives an input from the user and do whatever the user writes, to do this we need to check several conditions at the same time (aka a nesting of conditions): if the user wants to exit, pay, go back, go next or add the item to the list. As you can see it took me a lot of space to write those conditions in the regular way. If the first condition didn´t work it will pass to the else that is another condition and if that condition is false it will pass the the next else that is another condition and it keeps going on until one condition is true or it reaches the final else. The easy and clean way to do it is with the elif, let´s see an example of the same program but this time with elifs:
x = input(“¿What do you want to do next?”)
if x == “exit”:
#close the program
elif x == “pay”:
#go to the pay window
elif x == “back”:
#move to the previous window
elif x == “next”:
#move to the next window
elif x == “add”:
#add the item to the shopping list
else:
print (“please write exit, pay, back, next or add”)
This program do exaclty the same but it took me less time to write it and is easier to understand than the other one. The elif is like the combination of else-if, Python reads it exactly in the same way.
Notice that each elif is used as an if, with the condition by the side, the “:” at the end and the instructions are indented. To finish the nesting of conditions we put an else just as if it were a normal if/else. If the user writes “back” the first and second conditions will be false and it will execute the code inside the second elif. Have in mind that after the program ends executing the code inside the elif it will jump to the end of the nesting and continue going, what i mean is that the program will not continue checking if the other conditions are true because one has already been executed. Also, the program reads from top to botton the conditions, not at the same time; so if two conditions are true it will only execute the first one. Let´s see an example of this:
x = 3
if x > 0:
print (“X is greater than 0”)
elif x < 10:
print (“X is less than ten”)
elif x < 0:
print (“X is a negative number”)
else:
print (“X is greater than 10”)
X is greater than cero
Well, what´s wrong with this program? What´s wrong is that no matter what number you put, it will print “X is greater than 0” or “X is a negative number” completely ignoring the other two conditions. Lets see, if we write a 9 it should print “X is less than then” but also the first condition is true so it should also print “X is greater than 0” but as a nesting of conditions can only take one condition it will go for the first one to be true si it will print “X is greater than 0”. If we write number 20 the first condition to be true will be x > 0 so it will print “X is greater than 0” again. Just in case that you write a negative number it will print “X is a negative number” but for all the other numbers the first condition will always be true first. If you want to make a good condition nesting with elif (also with else/if) always have in mind which condition you give the preference. Nothing happens if two or more conditions are true, the program can still work as you want if you put them in the right order. I recommend you to order the condition from specific to general, in that way if the specific condition is true but also the general is true the program is going to take the specific condition first. Here is the same program but this time taking all the posibilities from the specific to the general:
x =0
if x == 0:
print (“X is equal to 0”)
elif x < 10:
print (“X is less than ten”)
elif x > 10:
print (“X is greater than 10”)
else:
print (“X is a negative number or is a string”)
X is equal to 0
A condition is an operation used in programs to see if something is true or not. These conditionals help you doing ac action whenever they are true. During this post I will guide you on how to use them properly for the creation of a program:
First of all we need to understand which ones are these conditionals.
The first one is called IF. We place it in the middle of out code to see if a condition is true or false. We can only place it once, the rest of the conditions will be evaluated by a different function.
The second one is ELIF. This one can be used to evaluate many conditions along the same IF. This function can be used as many times as you want, as long as you state the word “elif” followed by the statement you want to evalute.
ELSE is the last conditional. It is use to stablish what will happen in case none of the conditions above is true.
Now, we are creating a program that will evaluate a given number and show if it´s positive, negative or 0.
So we start by asking the user for a number.
How we start with our first condition; if the number is greater than zero, then it´s a positive number. So, for this we need to type if followed by the condition that would be x>0. At the end of the line we place a colon ( : ).
After this, we need the program to let the user know that the number is positive, se we create an output. This output need to be intended to show that is the action the computer should do in case the condition is true.
If this condition is not true, then it means that the number is zero or a negative number. To differentiate if this number is zero or negative we will need another conditional. But as we explained before, this conditional cannot be an IF conditional, but an ELIF.
An ELIF conditional works just an IF conditional: you place the word “elif” followed by the condition “x==0” and ending with a colon. Now the condition we will be evaluating is if the number is equal to zero. (It is necessary to place two equal signs to evaluate)
If none of this conditions are true, then we know that the number given by the user if not zero or greater than zero; therefore, this number is lower than zero. We know that the only numbers that are lower than zero are negative numbers.
Based on the previous reasoning, if this numbers fails to be true in both conditionals, then it is a negative number.
Now we know we don´t need to evaluate in any other condition so we can use the conditional ELSE. For this, we only write the word “else” followed by a colon. That, we just need to type the action we want the computer to do.
And this is what will happen when you run this program:
SWITCH es una condicional, pero más compleja ya que incluye casos para validar la expresión condicional. Si no es uno de los casos mencionados, es lo que resta. The blog that helped me (where did I get the definitions and… Continue Reading →