xxxxxxxxxx
# You can use 'in' on a dictionary to check if a key exists
d = {"key1": 10, "key2": 23}
"key1" in d
# Output:
# True
xxxxxxxxxx
d = {"key1": 10, "key2": 23}
if "key1" in d:
print("this will execute")
if "nonexistent key" in d:
print("this will not")
xxxxxxxxxx
d = {"apples": 1, "banannas": 4}
# Preferably use .keys() when searching for a key
if "apples" in d.keys():
print(d["apples"])
xxxxxxxxxx
dict = { "How":1,"you":2,"like":3,"this":4}
key = "this"
if key in dict.keys():
print("present")
print("value =",dict[key])
else:
print("Not present")
xxxxxxxxxx
if word in data:
return data[word]
else:
return "The word doesn't exist. Please double check it."
xxxxxxxxxx
# Example dictionary
my_dict = {"key1": "value1", "key2": "value2", "key3": "value3"}
# Method 1: Using `in` operator
if "key2" in my_dict:
print("Key 'key2' exists in dictionary.")
# Method 2: Using `get()` method
if my_dict.get("key2"):
print("Key 'key2' exists in dictionary.")
xxxxxxxxxx
# Dictionary
my_dict = {"apple": 1, "banana": 2, "orange": 3}
# Method 1: Using the "in" operator
if "apple" in my_dict:
print("Key 'apple' exists in the dictionary")
else:
print("Key 'apple' does not exist in the dictionary")
# Method 2: Using the get() method
if my_dict.get("banana"):
print("Key 'banana' exists in the dictionary")
else:
print("Key 'banana' does not exist in the dictionary")
# Method 3: Using the keys() method
if "orange" in my_dict.keys():
print("Key 'orange' exists in the dictionary")
else:
print("Key 'orange' does not exist in the dictionary")
xxxxxxxxxx
# in tests for the existence of a key in a dict:
d = {"key1": 10, "key2": 23}
if "key1" in d:
print("this will execute")
if "nonexistent key" in d:
print("this will not")
# Use dict.get() to provide a default value when the key does not exist:
d = {}
for i in range(10):
d[i] = d.get(i, 0) + 1
# To provide a default value for every key, either use dict.setdefault() on each assignment:
d = {}
for i in range(10):
d[i] = d.setdefault(i, 0) + 1
# or use defaultdict from the collections module:
from collections import defaultdict
d = defaultdict(int)
for i in range(10):
d[i] += 1
xxxxxxxxxx
my_dict = {'name': 'John', 'age': 25, 'country': 'USA'}
# Method 1: Using the 'in' operator
if 'age' in my_dict:
print("Key 'age' exists in the dictionary.")
else:
print("Key 'age' does not exist in the dictionary.")
# Method 2: Using the 'get' method
if my_dict.get('country') is not None:
print("Key 'country' exists in the dictionary.")
else:
print("Key 'country' does not exist in the dictionary.")
xxxxxxxxxx
hh = {"a":3, "b":4, "c":5}
# check if a key exists
print("b" in hh)
# True