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How to Loop Through a Dictionary in Python

If you want to go through the contents of a dictionary in Python, there are three main patterns to know:

  • loop through keys
  • loop through values
  • loop through keys and values together

This page shows the most useful ways to do that with simple examples.

Quick answer #

student = {"name": "Ana", "age": 20, "city": "Lima"}

for key, value in student.items():
    print(key, value)

Output:

name Ana
age 20
city Lima

Use .items() when you need both the key and the value during the loop.

What this page helps you do #

  • Loop through dictionary keys
  • Loop through dictionary values
  • Loop through both keys and values
  • Choose the right method for your task

Start with a simple dictionary #

A dictionary stores data as key-value pairs.

In this example:

  • "name" is a key
  • "Ana" is its value
student = {
    "name": "Ana",
    "age": 20,
    "city": "Lima"
}

Expected printed output for this dictionary might look like this, depending on how you loop:

name
age
city

or:

Ana
20
Lima

or:

name Ana
age 20
city Lima

If dictionaries are new to you, see Python dictionaries explained.

Loop through dictionary keys #

A basic for loop over a dictionary gives you the keys by default.

student = {
    "name": "Ana",
    "age": 20,
    "city": "Lima"
}

for key in student:
    print(key)

Output:

name
age
city

Use this when you only need the keys.

You can also write the same thing with .keys():

for key in student.keys():
    print(key)

This works too, but it is often not necessary. A plain loop over the dictionary is shorter and does the same job.

If you want to work directly with dictionary keys, see the dict.keys() method.

Loop through dictionary values #

Use .values() when you want only the values.

student = {
    "name": "Ana",
    "age": 20,
    "city": "Lima"
}

for value in student.values():
    print(value)

Output:

Ana
20
Lima

This is useful when the keys do not matter.

For more detail, see the dict.values() method.

Loop through keys and values together #

Use .items() when you need both parts of each dictionary entry.

student = {
    "name": "Ana",
    "age": 20,
    "city": "Lima"
}

for key, value in student.items():
    print(key, value)

Output:

name Ana
age 20
city Lima

This is the most common pattern for printing or processing dictionary contents.

You can format the output more clearly if you want:

for key, value in student.items():
    print(f"{key}: {value}")

Output:

name: Ana
age: 20
city: Lima

If you want a method-focused explanation, see the dict.items() method.

When to use each approach #

Use the loop style that matches your task:

  • Use for key in data: when you need keys only
  • Use for value in data.values(): when you need values only
  • Use for key, value in data.items(): when you need both

Examples:

student = {
    "name": "Ana",
    "age": 20,
    "city": "Lima"
}

# Keys only
for key in student:
    print("Key:", key)

# Values only
for value in student.values():
    print("Value:", value)

# Keys and values
for key, value in student.items():
    print(key, "->", value)

Common beginner mistakes #

1. Trying to unpack a plain dictionary loop into key and value #

This is wrong:

student = {"name": "Ana", "age": 20}

for key, value in student:
    print(key, value)

A plain dictionary loop returns only keys, not key-value pairs.

Use .items() instead:

for key, value in student.items():
    print(key, value)

2. Forgetting parentheses in .items() or .values() #

These are methods, so you must call them with parentheses.

Wrong:

for value in student.values:
    print(value)

Correct:

for value in student.values():
    print(value)

3. Changing dictionary size during the loop #

Be careful about adding or removing keys while looping.

Problem example:

student = {"name": "Ana", "age": 20, "city": "Lima"}

for key in student:
    if key == "age":
        del student[key]

This can raise an error because the dictionary size changes during iteration.

A safer approach is to loop over a copy of the keys:

student = {"name": "Ana", "age": 20, "city": "Lima"}

for key in list(student.keys()):
    if key == "age":
        del student[key]

print(student)

Output:

{'name': 'Ana', 'city': 'Lima'}

Simple variations #

Use enumerate(data.items()) if you also need a counter #

If you want the position number as well as the key and value, use enumerate().

student = {"name": "Ana", "age": 20, "city": "Lima"}

for index, (key, value) in enumerate(student.items(), start=1):
    print(index, key, value)

Output:

1 name Ana
2 age 20
3 city Lima

If this pattern is new to you, see how to use enumerate() in Python.

Use an if statement inside the loop to filter results #

You can check conditions inside the loop.

student = {"name": "Ana", "age": 20, "city": "Lima"}

for key, value in student.items():
    if key != "city":
        print(key, value)

Output:

name Ana
age 20

Loop through nested dictionaries one level at a time #

If a value is another dictionary, loop through it separately.

student = {
    "name": "Ana",
    "grades": {
        "math": 90,
        "science": 85
    }
}

for key, value in student.items():
    print("Outer:", key, value)

    if isinstance(value, dict):
        for inner_key, inner_value in value.items():
            print("  Inner:", inner_key, inner_value)

Output:

Outer: name Ana
Outer: grades {'math': 90, 'science': 85}
  Inner: math 90
  Inner: science 85

Debugging dictionary loop problems #

If your loop is not working as expected, these quick checks can help:

print(data)
print(type(data))
print(data.keys())
print(data.values())
print(data.items())

These checks help you confirm:

  • that data is really a dictionary
  • what keys it contains
  • what values it contains
  • what key-value pairs Python sees

Common causes of problems include:

  • using for key, value in data instead of data.items()
  • calling items or values without parentheses
  • removing or adding keys during iteration
  • confusing dictionary loops with list loops

FAQ #

How do I loop through both key and value in a dictionary? #

Use:

for key, value in my_dict.items():
    print(key, value)

Does looping through a dictionary return keys or values? #

By default, looping through a dictionary returns keys.

for key in my_dict:
    print(key)

How do I get only dictionary values in a loop? #

Use:

for value in my_dict.values():
    print(value)

Can I change a dictionary while looping through it? #

It is safer not to change its size during the loop. If needed, loop through a copy of the keys first.

for key in list(my_dict.keys()):
    # safe place to delete keys if needed
    pass

See also #

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