Learn K - 10 Code Examples & CST Typing Practice Test

K is a high-performance, array-oriented programming language designed for financial and analytical applications. It provides concise syntax for working with large datasets, time-series data, and complex calculations, and is often used in conjunction with the kdb+ database system.

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K Counter and Theme Toggle K Fibonacci Sequence K Factorial Calculator K Prime Checker K Sum of Array K Reverse String K Multiplication Table K Celsius to Fahrenheit K Simple Alarm Simulation K Random Walk Simulation

Learn K with Real Code Examples

Updated Nov 20, 2025

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Code Sample Descriptions

K Counter and Theme Toggle

count:0
isDark:0

updateUI:{
    'Counter: ', string count
    'Theme: ', (if[isDark; 'Dark'; 'Light'])
}

increment:{
    count+:1
    updateUI[]
}

decrement:{
    count-:1
    updateUI[]
}

reset:{
    count:0
    updateUI[]
}

toggleTheme:{
    isDark:1-isDark
    updateUI[]
}

/ Simulate actions
updateUI[]
increment[]
increment[]
toggleTheme[]
decrement[]
reset[]

Demonstrates a simple counter with theme toggling using K variables and functional style.

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K Fibonacci Sequence

fib:0 1
10{fib,:{x,y:x+y} last 2 fib}

Generates first 10 Fibonacci numbers using K arrays.

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K Factorial Calculator

fact:{[n] $[n=0;1;n*fact[n-1]]}
fact[5]

Calculates factorial of a number using K's functional style.

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K Prime Checker

isPrime:{[n] n>1 & all n mod 2_til n-1}
isPrime[13]

Checks if a number is prime using modulo and all.

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K Sum of Array

+/ 1 2 3 4 5

Calculates the sum of an array.

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K Reverse String

'HELLO' _/

Reverses a string.

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K Multiplication Table

{x*til 10}[5]

Generates multiplication table for a number.

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K Celsius to Fahrenheit

{x*9%5+32}[25]

Converts Celsius to Fahrenheit.

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K Simple Alarm Simulation

temp:80
thresh:75
$[temp>thresh;'Alarm: Temp Too High!';'Temp Normal']

Simulates an alarm if threshold exceeded.

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K Random Walk Simulation

steps:10
pos:0
10{pos+:2?2-1; pos}

Simulates a 1D random walk.

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Frequently Asked Questions about K

What is K?

What are the primary use cases for K?

Financial analytics and trading systems. Real-time market data processing. Time-series data analysis. High-performance data querying. Integration with kdb+ database for analytics

What are the strengths of K?

High-speed processing for large datasets. Extremely concise code for complex operations. Ideal for time-series and financial data. Seamless integration with kdb+ database. Functional and tacit programming allows elegant solutions

What are the limitations of K?

Steep learning curve due to terse syntax. Limited general-purpose use outside analytics. Small community compared to mainstream languages. Challenging debugging due to compact code. Requires kdb+ for many production use cases

How can I practice K typing speed?

CodeSpeedTest offers 10+ real K code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Learn K - 10 Code Examples & CST Typing Practice Test

Code Sample Descriptions

K Counter and Theme Toggle

count:0
isDark:0

updateUI:{
    'Counter: ', string count
    'Theme: ', (if[isDark; 'Dark'; 'Light'])
}

increment:{
    count+:1
    updateUI[]
}

decrement:{
    count-:1
    updateUI[]
}

reset:{
    count:0
    updateUI[]
}

toggleTheme:{
    isDark:1-isDark
    updateUI[]
}

/ Simulate actions
updateUI[]
increment[]
increment[]
toggleTheme[]
decrement[]
reset[]

Demonstrates a simple counter with theme toggling using K variables and functional style.

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K Fibonacci Sequence

fib:0 1
10{fib,:{x,y:x+y} last 2 fib}

Generates first 10 Fibonacci numbers using K arrays.

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K Factorial Calculator

fact:{[n] $[n=0;1;n*fact[n-1]]}
fact[5]

Calculates factorial of a number using K's functional style.

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K Prime Checker

isPrime:{[n] n>1 & all n mod 2_til n-1}
isPrime[13]

Checks if a number is prime using modulo and all.

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K Sum of Array

+/ 1 2 3 4 5

Calculates the sum of an array.

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K Reverse String

'HELLO' _/

Reverses a string.

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K Multiplication Table

{x*til 10}[5]

Generates multiplication table for a number.

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K Celsius to Fahrenheit

{x*9%5+32}[25]

Converts Celsius to Fahrenheit.

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K Simple Alarm Simulation

temp:80
thresh:75
$[temp>thresh;'Alarm: Temp Too High!';'Temp Normal']

Simulates an alarm if threshold exceeded.

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K Random Walk Simulation

steps:10
pos:0
10{pos+:2?2-1; pos}

Simulates a 1D random walk.

Let’s Try →

Frequently Asked Questions about K

What is K?

What are the primary use cases for K?

Financial analytics and trading systems. Real-time market data processing. Time-series data analysis. High-performance data querying. Integration with kdb+ database for analytics

What are the strengths of K?

What are the limitations of K?

How can I practice K typing speed?

CodeSpeedTest offers 10+ real K code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.