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S1Q1 · Classify Temperature

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Function: classify_temperature(temp: str) -> str

Core idea: strip the unit, convert Kelvin to Celsius if needed, then classify.

def classify_temperature(temp: str) -> str:
    if temp.endswith("K"):
        celsius = float(temp[:-1]) - 273.15
    else:
        celsius = float(temp[:-1])
    if celsius < 15:
        return "Cold"
    elif celsius <= 30:
        return "Moderate"
    else:
        return "Hot"

Key rules: - Unit is the last character: "C" or "K" - temp[:-1] strips the unit to get the numeric value - Kelvin → Celsius: K - 273.15 - Cold: < 15°C | Moderate: 15°C to 30°C inclusive | Hot: > 30°C

Template Code

def classify_temperature(temp: str) -> str:
    '''
    Classify a temperature given as a string with unit C or K.

    Convert Kelvin to Celsius using: °C = K - 273.15
    Classification:
        "Cold"     if celsius < 15
        "Moderate" if 15 <= celsius <= 30
        "Hot"      if celsius > 30

    Examples:
    >>> classify_temperature("10C")
    "Cold"
    >>> classify_temperature("20C")
    "Moderate"
    >>> classify_temperature("290K")
    "Moderate"

    Args:
        temp (str): Temperature string ending with "C" or "K"

    Returns:
        str: "Cold", "Moderate", or "Hot"
    '''
    ...

Problem Statement

Problem

Write a function classify_temperature(temp) that parses a temperature string, converts Kelvin to Celsius if needed, and returns the classification.

Examples:

Input 
"10C"
Output 
"Cold"
Input 
"290K"
Output 
"Moderate"
Input 
"310K"
Output 
"Hot"
Input 
"-5C"
Output 
"Cold"

Tracing all examples

Input Unit Value Celsius Classification
"10C" C 10 10.0 10 < 15 → Cold
"20C" C 20 20.0 15 ≤ 20 ≤ 30 → Moderate
"35C" C 35 35.0 35 > 30 → Hot
"290K" K 290 16.85 15 ≤ 16.85 ≤ 30 → Moderate
"310K" K 310 36.85 36.85 > 30 → Hot
"-5C" C -5 -5.0 -5 < 15 → Cold

Solution approaches

def classify_temperature(temp: str) -> str:
    if temp.endswith("K"):
        celsius = float(temp[:-1]) - 273.15
    else:
        celsius = float(temp[:-1])
    if celsius < 15:
        return "Cold"
    elif celsius <= 30:
        return "Moderate"
    else:
        return "Hot"

def classify_temperature(temp: str) -> str:
    unit  = temp[-1]
    value = float(temp[:-1])

    if unit == "K":
        celsius = value - 273.15
    else:
        celsius = value

    if celsius < 15:
        return "Cold"
    elif celsius <= 30:
        return "Moderate"
    else:
        return "Hot"

def classify_temperature(temp: str) -> str:
    value = float(temp[:-1])
    celsius = value - 273.15 if temp.endswith("K") else value

    if celsius < 15:    return "Cold"
    if celsius <= 30:   return "Moderate"
    return "Hot"

classify_temperature = lambda temp: (
    (lambda c: "Cold" if c < 15 else "Moderate" if c <= 30 else "Hot")
    (float(temp[:-1]) - (273.15 if temp.endswith("K") else 0))
)

Inner lambda classifies; the ternary in the outer call handles unit conversion. All in one expression.

Key takeaways

01

temp[:-1] strips the unit

The last character is always the unit ('C' or 'K'). Slicing with [:-1] removes it, leaving the numeric string ready for float(). Works for negative values like "-5C" too.

02

K - 273.15 converts to Celsius

0°C = 273.15 K. Always subtract 273.15 when converting from Kelvin. Only apply conversion for 'K' - leave Celsius values unchanged.

03

Boundary values: 15 and 30 are Moderate

The ranges are: Cold is strictly less than 15; Moderate is 15 to 30 inclusive; Hot is strictly greater than 30. Use < 15 then <= 30 to get this right.