The insertion order is maintained in the dictionary since version Python 3.7.
You can find the first key in the dictionary in Python using the list(yourdict.keys())[0] method.
Basic Example
yourdict = {
"one": 1,
"two": 2,
"three": 3,
"four": 4
}
first_key = list(yourdict.keys())[0]
print(first_key)
Output
one
This tutorial is only applicable only if you’re using Python version 3.7 or later.
If you try to get the first in the dictionary with python versions earlier than 3.7, you may get any random keys because of non-maintenance of the insertion order.
Different methods are available to find the first key in the dictionary in Python. Let us learn each method.
Checking Python Version Information
Python dictionaries are ordered since version 3.7.
You can check the python version using the below script.
Code
import sys
print(sys.version)
Output
3.8.2 (default, Sep 4 2020, 00:03:40) [MSC v.1916 32 bit (Intel)]
Using Keys() And List function
The keys()
method returns a copy of the dictionary’s list of keys.
To find the first key of the dictionary,
- Convert the dictionary keys into a
list
using the list() method. - Access the first item in the list using the index
0
.
Use this method when you just want the first key of the dictionary.
Code
yourdict = {
"one": 1,
"two": 2,
"three": 3,
"four": 4
}
first_key = list(yourdict.keys())[0]
print(first_key)
Output
one
Using Items() and For Loop
The items()
method returns the key-value pair of the dictionary.
To find the first key of the dictionary using the items()
method,
- Get the
items()
and iterate it over items the for loop - Print the key during the first iteration and break to ignore the other items in the dictionary.
Use this method when you want the key and value of the first item in the dictionary.
Code
yourdict = {
"one": 1,
"two": 2,
"three": 3,
"four": 4
}
for k,v in yourdict.items():
print(k)
break
Output
one
Using Iters() method
The iters()
method returns an iterator object of the dictionary.
To get the first key of the dictionary,
- Get the iterator object of the dictionary using the
iters()
method - Move the cursor in the iterator to the first item using the
next()
method. You’ll have the first key in the dictionary.
Use it only when you need an iterator object of the dictionary and need to move forward or backwards during the iteration.
Code
yourdict = {
"one": 1,
"two": 2,
"three": 3,
"four": 4
}
dict_iterator = iter(yourdict)
print(next(dict_iterator))
Output
one
Get First N Keys In the Dictionary
To find the first N keys,
- Get the list of keys using the
keys()
method - Use the list slicing to get the first
n
keys.
For example, to get the first two items, use :2
.
Code
yourdict = {
"one": 1,
"two": 2,
"three": 3,
"four": 4
}
n = 2
first_n_keys = list(yourdict.keys())[:n]
print(first_n_keys)
Output
['one', 'two']