Hi, this is Milo, a blogger who would like to share his test development techniques, interview tips and growing experiences with you!

Welcome everyone to pay attention to my public number: test development pit goods.

Let’s have a fun day and do a little trick of ignoring (discarding) variables.

Everybody knows that

Most people know about multivariable assignment, such as:

a, b = 1.2
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You should also know that swapping variables can be done without generating temporary variables:

a, b = b, a
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Abandoned variable

So today I’m going to show you a different one. As we know, variables start with a letter and can be followed by a letter/number/underscore. What happens if the variables are named separately with an underscore?

As you can see, no error is reported, which means the operation is accepted. Variables named _ are automatically discarded as obsolete variables.

Usage scenarios

For example, if I want to execute a method N times, but I don’t care how many times I execute it, I can write:

def func() :
    print("yyds")
    
n = 10
for _ in range(n):
    func()
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Since we don’t need this I, we can set it to _.

Let’s think about whether we can also use this when we assign to arrays. Let’s say I have an array that looks like this:

a = ["Top dog"."190cm"."3 sets of siheyuan"."Love to play ball"."Very handsome."."Married"]
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You can see that the order of the array is: name, height, real estate, hobbies, appearance, and marital status. As a girl, I care more about his height, real estate, appearance and marital status.

For comparison, I have a number of similar blind dates that I will consider. So I’m going to list all of these conditions.

Let’s look at the original way:

height = a[1]
house = a[2]
feature = a[4]
married = a[5]
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But if you use _ to discard some variables, you can write:

_, height, house, _, feature, married = a
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So you can get rid of the variables that you don’t want, which isn’t very useful to be honest. But it’s a trick. Did you Get it?