The same plot in 14 other libraries — Python: Bokeh, lets-plot, Matplotlib, Plotly, plotnine, Pygal, Seaborn; R: ggplot2; Julia: Makie.jl; JavaScript: Chart.js, D3.js, Apache ECharts, Highcharts, MUI X Charts. Compare all 15 side by side: Basic Pyramid Chart in Python, R, Julia and JavaScript.
A pyramid chart displays two opposing horizontal bar charts that share a central axis, creating a pyramid or butterfly shape. This visualization is ideal for comparing two related metrics across the same categories, revealing asymmetries and patterns in bidirectional data. Most commonly used for population pyramids showing age-gender distributions.
""" anyplot.ai
pyramid-basic: Basic Pyramid Chart
Library: altair 6.3.0 | Python 3.14.9
Quality: 83/100 | Updated: 2026-11-01
"""
import importlib
import os
import sys
# Drop script directory from sys.path so the `altair` package resolves, not this file
sys.path[:] = [p for p in sys.path if os.path.abspath(p or ".") != os.path.dirname(os.path.abspath(__file__))]
alt = importlib.import_module("altair")
np = importlib.import_module("numpy")
pd = importlib.import_module("pandas")
Image = importlib.import_module("PIL.Image")
# Theme tokens
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
# Imprint palette: all eight positions in canonical order
IMPRINT_PALETTE = ["#009E73", "#C475FD", "#4467A3", "#BD8233", "#AE3030", "#2ABCCD", "#954477", "#99B314"]
# Columns: set these to your table's column names
AGE_GROUP = "Age group" # role: category
MALE = "Male" # role: value_left
FEMALE = "Female" # role: value_right
SIDE = "Gender" # role: extra
# Data: replace this block with your own table, for example df = pd.read_csv("population.csv")
df = pd.DataFrame(
{
AGE_GROUP: ["0-9", "10-19", "20-29", "30-39", "40-49", "50-59", "60-69", "70-79", "80+"],
MALE: [4.8, 5.2, 6.1, 7.3, 8.5, 7.8, 5.9, 3.2, 1.2],
FEMALE: [4.5, 5.0, 6.3, 7.5, 8.7, 8.2, 6.8, 4.8, 2.5],
}
)
# Plot: reads only df and the constants above
ESCAPE = str.maketrans({".": "\\.", "[": "\\[", "]": "\\]", ":": "\\:"})
VALUE = "Population (millions)"
SIGNED = "Signed value"
sides = [MALE, FEMALE]
long = df.melt(id_vars=AGE_GROUP, value_vars=sides, var_name=SIDE, value_name=VALUE)
long[SIGNED] = np.where(long[SIDE] == MALE, -long[VALUE], long[VALUE])
limit = float(np.ceil(long[VALUE].max() / 2) * 2 + 2)
# Interactive highlight — click legend to isolate a side
selection = alt.selection_point(fields=[SIDE], bind="legend")
chart = (
alt.Chart(long)
.mark_bar(cornerRadiusEnd=2)
.encode(
y=alt.Y(
AGE_GROUP.translate(ESCAPE),
type="ordinal",
title=AGE_GROUP,
sort="descending",
axis=alt.Axis(titleFontSize=12, labelFontSize=10),
),
x=alt.X(
SIGNED.translate(ESCAPE),
type="quantitative",
title=VALUE,
axis=alt.Axis(titleFontSize=12, labelFontSize=10, labelExpr="abs(datum.value)", tickMinStep=2),
scale=alt.Scale(domain=[-limit, limit], nice=False),
),
color=alt.Color(
SIDE.translate(ESCAPE),
type="nominal",
title=SIDE,
sort=None,
scale=alt.Scale(domain=sides, range=IMPRINT_PALETTE[: len(sides)]),
legend=alt.Legend(titleFontSize=10, labelFontSize=10, orient="bottom"),
),
opacity=alt.condition(selection, alt.value(0.9), alt.value(0.25)),
tooltip=[
alt.Tooltip(SIDE.translate(ESCAPE), type="nominal", title=SIDE),
alt.Tooltip(AGE_GROUP.translate(ESCAPE), type="ordinal", title=AGE_GROUP),
alt.Tooltip(VALUE.translate(ESCAPE), type="quantitative", title=VALUE, format=".1f"),
],
)
.add_params(selection)
.properties(
width=620,
height=320,
background=PAGE_BG,
title=alt.Title(text="pyramid-basic · altair · anyplot.ai", fontSize=16, anchor="middle"),
)
.configure_view(fill=PAGE_BG, stroke=None)
.configure_axis(
domainColor=INK_SOFT, tickColor=INK_SOFT, gridColor=INK, gridOpacity=0.10, labelColor=INK_SOFT, titleColor=INK
)
.configure_title(color=INK)
.configure_legend(fillColor=ELEVATED_BG, strokeColor=INK_SOFT, labelColor=INK_SOFT, titleColor=INK, padding=6)
)
# Save
chart.save(f"plot-{THEME}.png", scale_factor=4.0)
chart.save(f"plot-{THEME}.html")
# Pad (never crop) to the canonical 3200 x 1800 canvas
TARGET_W, TARGET_H = 3200, 1800
img = Image.open(f"plot-{THEME}.png").convert("RGB")
w, h = img.size
if w > TARGET_W or h > TARGET_H:
raise SystemExit(f"altair produced {w}x{h}, exceeds {TARGET_W}x{TARGET_H}; shrink width/height")
if (w, h) != (TARGET_W, TARGET_H):
canvas = Image.new("RGB", (TARGET_W, TARGET_H), PAGE_BG)
canvas.paste(img, ((TARGET_W - w) // 2, (TARGET_H - h) // 2))
canvas.save(f"plot-{THEME}.png")
Runnable source as JSON, for any HTTP client: https://api.anyplot.ai/specs/pyramid-basic/altair/code. Any spec id and library id listed in llms-full.txt fit the same URL shape; every URL below is complete and callable.
{
"spec_id": "pyramid-basic",
"language": "python",
"library": "altair",
"page": "https://anyplot.ai/pyramid-basic/python/altair",
"hub": "https://anyplot.ai/pyramid-basic",
"code_json": "https://api.anyplot.ai/specs/pyramid-basic/altair/code",
"spec_json": "https://api.anyplot.ai/specs/pyramid-basic",
"render_light_png": "https://storage.googleapis.com/anyplot-images/plots/pyramid-basic/python/altair/plot-light.png",
"render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/pyramid-basic/python/altair/plot-dark.png",
"interactive_light_html": "https://storage.googleapis.com/anyplot-images/plots/pyramid-basic/python/altair/plot-light.html",
"interactive_dark_html": "https://storage.googleapis.com/anyplot-images/plots/pyramid-basic/python/altair/plot-dark.html",
"quality_score": 83.0,
"license": "MIT",
"guide": "https://anyplot.ai/llms.txt"
}Part of Basic Pyramid Chart on anyplot.ai.