Webbo3 Data Analysis Bootcamp · Excel Module · Lesson 2

Excel Data Types and Data Entry: Text, Numbers, Dates, Currency, AutoFill, Flash Fill, and Find and Replace

A hands on lesson covering how Excel reads and stores your data, how to enter and edit it correctly, and the tools that let you fill, fix, and find data fast.

In the last lesson you learned where everything sits on the Excel screen. This lesson is about what happens the moment you actually type something into a cell. Excel does not treat every piece of data the same way. A date is not stored the same way as the word "date." A number with a naira sign in front of it is not stored the same way as a plain number. If you do not understand this from day one, you will run into confusing errors later: formulas that refuse to calculate, dates that sort in the wrong order, numbers that align strangely in a column. This lesson fixes that at the root.

1. Data Types in Excel

Every cell in Excel holds one of a few underlying data types. Knowing which type you are dealing with tells you what Excel will let you do with that cell later, especially inside formulas.

Text. Anything Excel cannot interpret as a number, date, or formula is treated as text, and it is automatically aligned to the left of the cell. Names, addresses, product descriptions, and notes all fall here. One important detail: if you need a number to behave like text, for example a phone number that starts with a zero, or a code like 02415, you must format the cell as Text first, otherwise Excel will strip the leading zero or try to do math with it. Select the cell, press Ctrl + 1, choose Text under Category, then type your value.

Numbers. Plain numeric values are automatically aligned to the right of the cell, and Excel applies the General format by default, meaning it displays the number exactly as typed unless the column is too narrow, in which case it may switch to scientific notation like 2.5E+07. The actual value typed is always preserved and visible in the Formula Bar, even if the cell display looks different.

Dates. Excel actually stores every date as a serial number behind the scenes, counting days from a fixed starting point. This is why you can subtract one date from another and get a number of days as the answer. The moment you type something that looks like a date, for example 14/3/2026 or 14-Mar-26, Excel automatically converts it and right aligns it like a number. To change how a date displays without changing the actual stored value, select the cell, press Ctrl + 1, and choose Date, then pick a format such as Long Date for "14 March 2026" or Short Date for "14/03/2026."

Currency. The Currency format adds a currency symbol directly before the number, for example ₦45,000.00, and aligns the symbol right next to the digit. You can apply it by selecting your cells, pressing Ctrl + 1, choosing Currency, and picking your symbol from the dropdown. There is a quick keyboard shortcut too: select the cells and press Ctrl + Shift + $ to apply default currency formatting instantly.

Accounting. Accounting format also displays monetary values, but it behaves differently from Currency in two specific ways. First, the currency symbol is pushed all the way to the left edge of the cell while the number sits to the right, so when you stack several cells in a column, every symbol lines up in a neat vertical row, which makes financial statements far easier to scan. Second, negative numbers in Accounting format show in brackets instead of with a minus sign, and zero values display as a dash instead of "0.00." This is the format you will use constantly once you get into the Data Analysis bootcamp's financial modules, because it is the standard format used in real accounting and finance work. Apply it through Home tab → Number group → click the small dollar sign icon, or through Ctrl + 1 → Accounting.

A practical habit to build now: never assume Excel guessed your data type correctly. Click on any cell you have just entered and glance at how it aligns. Text sits left, numbers and dates sit right. If something looks off, check the Number group on the Home tab to confirm what format is actually applied.

2. Entering and Editing Data in Cells

There are three ways to get data into a cell, and each suits a different situation.

Direct typing. Click a cell, type your value, and press Enter to move down or Tab to move right. This is the most common method for everyday entry.

Editing an existing cell. Double click the cell to edit directly inside it, or single click the cell and press F2 to drop your cursor into edit mode without touching the mouse. You can also click once on the cell and then edit its contents inside the Formula Bar above, which is the better option when the entry is long, such as a full sentence or a complex formula, because you get more visible space to work in.

Clearing a cell properly. Pressing Delete removes the cell's contents but keeps its formatting. If you want to wipe both the data and the formatting back to a clean slate, go to Home tab → Editing group → Clear → Clear All. This matters more than it sounds. A cell that looks empty but still carries formatting (currency symbols, borders, fill colour) can confuse you later when you reuse that cell for something different.

A practical tip for long entries: if you need to add a line break inside a single cell, for example writing a multi line note, press Alt + Enter while typing instead of just Enter. Pressing Enter alone will move you to the next cell down and end your entry.

3. AutoFill Basics

Look at the bottom right corner of any selected cell and you will see a tiny black square. This is called the fill handle, and it is the engine behind AutoFill. Click and hold on it, then drag in any direction, and Excel extends whatever pattern it detects.

Single value, no pattern. If you select one cell with a plain word or number and drag the fill handle, Excel simply copies that same value into every cell you drag across.

Simple numeric series. Type 1 in one cell and 2 in the cell directly below it, select both cells together, then drag the fill handle down. Excel detects the pattern (increasing by 1) and continues it: 3, 4, 5, and so on. If your two starting numbers are 5 and 10, Excel detects the step size of 5 and continues 15, 20, 25.

Dates. Type a single date into one cell and drag the fill handle. Excel automatically increases the date by one day per cell, no second starting value needed, because dates are a recognised pattern type on their own.

Built in lists. Type "Monday" into a cell and drag the fill handle across or down, and Excel will continue with Tuesday, Wednesday, and the rest of the week automatically. The same works for month names and quarters like "Quarter 1." These are recognised as custom lists built into Excel.

Double click instead of dragging. If you have a long column of data beside the column you want to fill, double click the fill handle instead of dragging it manually, and Excel automatically fills all the way down to match the length of the adjacent column. This saves you from dragging hundreds of rows by hand.

Controlling what gets copied. After you drag and release, a small icon appears just below your selection called AutoFill Options. Click it to choose between Copy Cells, Fill Series, Fill Formatting Only, or Fill Without Formatting. This is useful when AutoFill copies formatting you did not want, such as borders or background colour, along with the values.

Holding Ctrl while dragging flips the behaviour. If Excel would normally continue a sequence, holding Ctrl while you drag makes it copy the same value instead. If Excel would normally just copy a single number, holding Ctrl while you drag makes it increment instead. This is a quick way to override AutoFill's guess without opening the options menu.

4. Flash Fill Basics

Flash Fill looks similar to AutoFill on the surface, but it solves a completely different problem. AutoFill extends a numeric or date pattern. Flash Fill detects a text transformation pattern based on an example you give it, and applies that exact transformation to the rest of the column. It does not write a formula behind the scenes. It simply learns the pattern from your example and fills in matching results as plain values.

Practical example, splitting a full name. Suppose column A holds full names like "Chidinma Okafor" and you want just the first name in column B. Type "Chidinma" into B2 manually, then press Enter. Click back into B3 and start typing the next first name, "Adewale" for example. Excel will usually show a faint preview filling the rest of the column automatically. Press Enter to accept it, or if no preview appears, select the range and press Ctrl + E to trigger Flash Fill manually.

Practical example, combining two columns. If column A has first names and column B has last names, type the combined full name into column C for the first row, for example "Chidinma Okafor," press Enter, then press Ctrl + E. Excel fills the rest of column C by combining the corresponding first and last name from each row.

Practical example, reformatting phone numbers. If a column has phone numbers stored as 10 raw digits like 8031234567 and you want them displayed as 0803-123-4567, manually type the correctly formatted version for the first entry, then press Ctrl + E. Flash Fill detects the punctuation pattern and applies it down the column.

Where Flash Fill struggles. If your data is inconsistent, for example some names have a middle initial and others do not, Flash Fill might misread the pattern from a single example. The fix is simple: give it two or three examples instead of one before pressing Ctrl + E, so Excel can identify the actual rule rather than guessing from one case. After running Flash Fill, always scroll through and spot check a handful of results before trusting the entire column, because it produces plain values with no formula to audit later. If something looks wrong, press Ctrl + Z immediately and try again with clearer examples.

5. Undo, Redo, Find, and Replace

Undo and Redo. Press Ctrl + Z to undo your last action, and you can press it repeatedly to step back through your recent history, often dozens of steps. Press Ctrl + Y to redo an action you just undid. These two shortcuts should become reflexive. Whenever AutoFill, Flash Fill, or a bulk Replace All goes wrong, your very first move should be Ctrl + Z, not panic.

Find. Press Ctrl + F to open the Find dialog. Type what you are searching for in the "Find what" box and press Enter, or click Find Next to jump to the first match, or click Find All to see every matching cell listed at once, with the option to click any item in that list to jump straight to it. Click Options inside the dialog to reveal extra settings: Within lets you restrict the search to the current sheet or expand it to the whole workbook, Match case makes the search respect uppercase and lowercase exactly, and Match entire cell contents restricts results to cells where the entire content equals exactly what you typed, rather than just containing it somewhere inside.

Replace. Press Ctrl + H to open Replace. Type the value you want to find in "Find what," type the new value in "Replace with," then choose Replace to swap one instance at a time so you can review each one, or Replace All to update every matching cell instantly across your search scope. Replace All does not ask for confirmation before each change, so treat it carefully. Always click Find All first to preview exactly what will be affected before committing to Replace All on a large sheet.

Wildcards for partial matches. Inside both Find and Replace, you can use the asterisk symbol to represent any number of unknown characters, and the question mark to represent exactly one unknown character. For example, searching "INV*" finds INV001, INV2024, and anything starting with INV. Searching "s?t" finds "sat" and "set" but not "salt," because the question mark only stands in for one character. If you genuinely need to search for a literal asterisk or question mark character, type a tilde directly before it, for example "~?" finds an actual question mark in your data.

A real workflow scenario for this bootcamp. Imagine you receive a sales dataset where the region is sometimes typed "Lagos," sometimes "LAGOS," and sometimes "lagos state." If you need every variation standardised to exactly "Lagos," do not use Replace All blindly, because it can affect partial matches you did not intend. Instead, press Ctrl + H, type "lagos state" in Find what with Match case turned off, type "Lagos" in Replace with, click Find All first to confirm exactly which cells will change, then click Replace All only once you are confident.

Using AI to Move Faster in Excel

Everything in this lesson is a manual skill worth knowing properly, because you need to recognise correct results and catch mistakes. But once you understand these tools, AI inside Excel becomes a genuine accelerator rather than a crutch. Here is exactly how to apply it to what you just learned.

1. Use Copilot to clean messy data types in seconds.
If you inherit a column where dates are typed in five different formats, or currency values are stored as plain text with stray naira signs mixed in, you can select the range and ask Copilot something like "Convert this column to a consistent date format" or "Identify which cells in this column are stored as text instead of numbers." This is the exact kind of repetitive cleanup task that used to take half an hour of manual checking, cell by cell.

2. Let AI do what Flash Fill cannot.
Flash Fill is genuinely powerful, but it only learns from the example you give it, and it can misfire on inconsistent data. For more complex transformations, for example extracting a state name out of a full address, or standardising five spelling variations of the same company name in one move, describe the exact transformation you want in plain language to Copilot, or use the =COPILOT() function directly in a cell, for example =COPILOT("Extract only the state from this address", A2). Where Flash Fill needs a clean unambiguous pattern, natural language description handles ambiguity far better.

3. Ask Copilot to spot what your eyes might miss before you run Replace All.
Before committing to a large Find and Replace operation across a whole workbook, you can ask Copilot to scan the column first, for example "List every unique spelling variation of region names in this column." This gives you the full picture of what Replace All would actually touch, which is safer than guessing and clicking Replace All directly.

4. Verify everything before you trust it.
This rule does not change no matter how good the tool gets. AI suggestions inside Excel, whether from Copilot's formula suggestions or the COPILOT function, should be checked against a handful of rows you can confirm by hand before you apply the result across an entire sheet. Treat AI output here exactly the way you treat Flash Fill output: useful, fast, but never assumed correct without a spot check.

A habit worth building from this lesson onward: whenever you catch yourself manually retyping or reformatting more than a handful of cells by hand, stop and ask whether Flash Fill, AutoFill, or Copilot could have detected that pattern for you instead. Data entry speed is one of the clearest places where AI inside Excel pays off immediately, because the patterns are usually obvious to a model the moment you show it one clean example.

Next lesson: basic formatting, conditional formatting, and your first formulas.