What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Use pd.crosstab() with its normalize argument to turn category counts into proportions. Choose "index" for row percentages, "columns" for column percentages, or "all" for each cell’s share of the whole table. These settings use different denominators, so select the one that matches the question you want the table to answer.
Create row, column, and overall percentages
Suppose df is a pandas DataFrame with categorical columns named group and outcome. Each crosstab cell represents a combination of those categories.
import pandas as pd
# Each row sums to 1: outcome distribution within each group.
row_pct = pd.crosstab(df["group"], df["outcome"], normalize="index")
# Each column sums to 1: group distribution within each outcome.
column_pct = pd.crosstab(df["group"], df["outcome"], normalize="columns")
# All cells together sum to 1: share of the full dataset.
overall_share = pd.crosstab(df["group"], df["outcome"], normalize="all")The denominator determines the interpretation:
normalize="index"divides each cell by its row total. Use it to ask how outcomes are distributed within each group.normalize="columns"divides each cell by its column total. Use it to ask how groups are distributed within each outcome.normalize="all"divides each cell by the total across the table. Use it to find each combination’s share of all observations.
The pandas API also accepts True for whole-table normalization and numeric forms such as 0 and 1. The pandas guide demonstrates normalize=True for global normalization and normalize="columns" for column normalization. Named strings make the intended denominator easier to read in instructional code. See the pandas.crosstab API reference and pandas guide to cross-tabulations.
Convert proportions to percentage values
Normalized crosstabs contain proportions on a 0-to-1 scale. For example, a cell value of 0.25 means one quarter of the observations for the selected denominator. To return numeric values on a 0-to-100 scale, multiply the result by 100:
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
row_pct_100 = row_pct.mul(100)State the denominator in a heading, table label, or accompanying explanation. “Outcome distribution within each group” describes row percentages; “share of all observations” describes overall percentages. The word “percentage” alone does not identify which calculation was used.
Add totals with margins
Set margins=True to add an All row and column. Use margins_name to give them a clearer label:
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
row_pct_with_totals = pd.crosstab(
df["group"],
df["outcome"],
normalize="index",
margins=True,
margins_name="Total",
)With normalization enabled, the margin values are normalized too. Check those totals against the chosen denominator before presenting the table; a margin should not be assumed to mean a raw count when the output is normalized.
When a crosstab is a count versus an aggregation
Without a values argument, pd.crosstab() produces a frequency table: it counts observations in each category combination. If you pass values, you must also supply aggfunc; pandas then aggregates those values within each combination. That is not automatically a percentage calculation. Before describing an aggregate as a percentage, define what its numerator and denominator mean.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
For broader reshaping or numeric aggregation workflows, pandas.pivot_table may be a better fit; its API documents aggregation options for pivoted data.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Check missing values, categories, and empty results
- Decide how to handle missing values. The
dropnaargument defaults toTrue; the API describes it as excluding columns whose entries are all NA. Decide whether missing categories belong in your analysis and inspect the resulting table before interpreting its denominator. - Account for unobserved categorical values. Categorical inputs can include categories with no observed instances, and those categories can appear in the output. A zero-observation category is not evidence of a positive share.
- Investigate an unexpectedly empty crosstab. The API notes that an empty DataFrame can result when the inputs have no overlapping indexes. Check that the input Series are aligned and that their indexes refer to the observations you intend to compare.
For the full argument definitions and behavior, consult the pandas.crosstab API reference.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
