Create app.py

app.py

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+# app.py
+# Simple Unit Converter for Hugging Face Spaces (Gradio)
+# No models or APIs required — pure Python
+
+import gradio as gr
+
+# Base units: Length -> meter, Mass -> kilogram, Volume -> liter
+UNITS = {
+    "Length": {
+        "m": 1.0,
+        "cm": 0.01,
+        "km": 1000.0,
+        "in": 0.0254,
+        "ft": 0.3048,
+        "yd": 0.9144,
+        "mi": 1609.344,
+    },
+    "Mass": {
+        "kg": 1.0,
+        "g": 0.001,
+        "lb": 0.45359237,
+        "oz": 0.028349523125,
+    },
+    "Volume": {
+        "L": 1.0,
+        "mL": 0.001,
+        "gal": 3.785411784,      # US liquid gallon
+        "qt": 0.946352946,       # US liquid quart
+        "cup": 0.2365882365,     # US cup
+    }
+}
+
+TEMP_UNITS = ["C", "F", "K"]
+CATEGORIES = ["Length", "Mass", "Temperature", "Volume"]
+
+
+def convert_temperature(value: float, from_u: str, to_u: str) -> float:
+    if from_u == "K" and value < 0:
+        raise ValueError("Kelvin cannot be negative.")
+    # to Celsius
+    if from_u == "C":
+        c = value
+    elif from_u == "F":
+        c = (value - 32.0) * 5.0 / 9.0
+    elif from_u == "K":
+        c = value - 273.15
+    else:
+        raise ValueError("Unknown temperature unit.")
+    # from Celsius to target
+    if to_u == "C":
+        return c
+    elif to_u == "F":
+        return c * 9.0 / 5.0 + 32.0
+    elif to_u == "K":
+        return c + 273.15
+    else:
+        raise ValueError("Unknown temperature unit.")
+
+
+def convert_via_base(value: float, category: str, from_u: str, to_u: str) -> float:
+    factors = UNITS[category]
+    if from_u not in factors or to_u not in factors:
+        raise ValueError("Unsupported unit for this category.")
+    base_val = value * factors[from_u]   # to base (meter/kg/liter)
+    return base_val / factors[to_u]
+
+
+def convert(category: str, value, from_unit: str, to_unit: str, decimals: int):
+    if value is None or str(value).strip() == "":
+        return "Please enter a number."
+    try:
+        value = float(value)
+    except:
+        return "Please enter a valid number (e.g., 12.5)."
+    try:
+        if category == "Temperature":
+            result = convert_temperature(value, from_unit, to_unit)
+        else:
+            result = convert_via_base(value, category, from_unit, to_unit)
+        fmt = f"{{:.{int(decimals)}f}}"
+        return f"{value} {from_unit} = {fmt.format(result)} {to_unit}"
+    except Exception as e:
+        return f"Error: {e}"
+
+
+def units_for_category(category: str):
+    if category == "Temperature":
+        choices = TEMP_UNITS
+    else:
+        choices = list(UNITS[category].keys())
+    default_from = choices[0]
+    default_to = choices[1] if len(choices) > 1 else choices[0]
+    return (
+        gr.update(choices=choices, value=default_from),
+        gr.update(choices=choices, value=default_to),
+    )
+
+
+with gr.Blocks(title="Simple Unit Converter") as demo:
+    gr.Markdown(
+        """
+        # Simple Unit Converter
+        A tiny web app to convert units (Length, Mass, Volume, Temperature).
+        No models or APIs — pure Python.
+        """
+    )
+
+    with gr.Row():
+        category = gr.Dropdown(CATEGORIES, value="Length", label="Category")
+        decimals = gr.Slider(minimum=0, maximum=10, step=1, value=3, label="Decimal places")
+
+    value_in = gr.Number(label="Input value", value=1.0)
+
+    with gr.Row():
+        from_unit = gr.Dropdown(list(UNITS["Length"].keys()), value="m", label="From unit")
+        to_unit = gr.Dropdown(list(UNITS["Length"].keys()), value="ft", label="To unit")
+
+    convert_btn = gr.Button("Convert")
+    output = gr.Textbox(label="Result", lines=1)
+
+    category.change(fn=units_for_category, inputs=category, outputs=[from_unit, to_unit])
+
+    convert_btn.click(fn=convert, inputs=[category, value_in, from_unit, to_unit, decimals], outputs=output)
+
+    gr.Examples(
+        examples=[
+            ["Length", 1, "m", "ft", 3],
+            ["Length", 12, "in", "cm", 2],
+            ["Mass", 2.5, "kg", "lb", 3],
+            ["Volume", 3, "L", "gal", 4],
+            ["Temperature", 100, "C", "F", 1],
+            ["Temperature", 300, "K", "C", 2],
+        ],
+        inputs=[category, value_in, from_unit, to_unit, decimals],
+        label="Examples (click to fill the form)"
+    )
+
+if __name__ == "__main__":
+    # Spaces runs your script and will serve the Gradio app automatically.
+    demo.launch()