Colon operator for ranges in MATLAB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple colon operator range

What is the output of this MATLAB code?

a = 3:7;

MATLAB

a = 3:7;

A [7 6 5 4 3]

B [3 5 7]

C [3 4 5 6 7]

D [3 4 5 6]

💡 Hint

The colon operator creates a vector starting at the first number and ending at the second, increasing by 1 by default.

The colon operator a:b creates a row vector starting at a, ending at b, with step size 1. So 3:7 is [3 4 5 6 7].

❓ Predict Output

intermediate

Output with custom step size in colon operator

What is the output of this MATLAB code?

b = 1:2:9;

MATLAB

b = 1:2:9;

A [1 4 7]

B [1 3 5 7 9]

C [1 2 3 4 5 6 7 8 9]

D [2 4 6 8]

💡 Hint

The colon operator with three parts is start:step:end.

1:2:9 means start at 1, add 2 each time, stop before exceeding 9. So the vector is [1 3 5 7 9].

❓ Predict Output

advanced

Output when step size does not evenly fit range

What is the output of this MATLAB code?

c = 0:0.3:1;

MATLAB

c = 0:0.3:1;

A [0 0.3 0.6 0.9 1.2]

B [0 0.3 0.6]

C [0 0.3 0.6 0.9 1.0]

D [0 0.3 0.6 0.9]

💡 Hint

The colon operator stops before exceeding the end value.

Starting at 0, adding 0.3 each time: 0, 0.3, 0.6, 0.9, next would be 1.2 which is >1, so stop at 0.9.

❓ Predict Output

advanced

Output of colon operator with negative step

What is the output of this MATLAB code?

d = 5:-1:1;

MATLAB

d = 5:-1:1;

A [5 4 3 2 1]

B [1 2 3 4 5]

C [5 4 3 2]

D [5 6 7 8 9]

💡 Hint

The colon operator can count down if the step is negative.

5:-1:1 counts down from 5 to 1 by subtracting 1 each step, so the vector is [5 4 3 2 1].

🧠 Conceptual

expert

Number of elements in colon operator range

How many elements are in the vector created by this MATLAB code?

e = 2:0.5:5;

MATLAB

e = 2:0.5:5;

A 7

B 6

C 9

D 8

💡 Hint

Count elements starting at 2, adding 0.5 until you reach or pass 5.

Elements are 2, 2.5, 3, 3.5, 4, 4.5, 5.0. That's 7 elements, so answer is 7.