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-rw-r--r--python3.html.markdown31
1 files changed, 26 insertions, 5 deletions
diff --git a/python3.html.markdown b/python3.html.markdown
index f6babaff..c3e2ede5 100644
--- a/python3.html.markdown
+++ b/python3.html.markdown
@@ -61,6 +61,17 @@ False
not True # => False
not False # => True
+# Boolean Operators
+# Note "and" and "or" are case-sensitive
+True and False #=> False
+False or True #=> True
+
+# Note with ints
+0 and 2 #=> 0
+-5 or 0 #=> -5
+0 == False #=> True
+2 == True #=> False #only 1 == True #=> True
+
# Equality is ==
1 == 1 # => True
2 == 1 # => False
@@ -127,7 +138,8 @@ bool({}) #=> False
# Python has a print function
print("I'm Python. Nice to meet you!")
-# No need to declare variables before assigning to them. Convention is to use lower_case_with_underscores
+# No need to declare variables before assigning to them.
+# Convention is to use lower_case_with_underscores
some_var = 5
some_var # => 5
@@ -176,7 +188,8 @@ li[::-1] # => [3, 4, 2, 1]
del li[2] # li is now [1, 2, 3]
# You can add lists
-li + other_li # => [1, 2, 3, 4, 5, 6] - Note: values for li and for other_li are not modified.
+# Note: values for li and for other_li are not modified.
+li + other_li # => [1, 2, 3, 4, 5, 6]
# Concatenate lists with "extend()"
li.extend(other_li) # Now li is [1, 2, 3, 4, 5, 6]
@@ -215,14 +228,17 @@ filled_dict = {"one": 1, "two": 2, "three": 3}
# Look up values with []
filled_dict["one"] # => 1
-# Get all keys as a list with "keys()". We need to wrap the call in list() because we are getting back an iterable. We'll talk about those later.
-list(filled_dict.keys()) # => ["three", "two", "one"]
+# Get all keys as a list with "keys()".
+# We need to wrap the call in list() because we are getting back an iterable. We'll talk about those later.
# Note - Dictionary key ordering is not guaranteed.
# Your results might not match this exactly.
+list(filled_dict.keys()) # => ["three", "two", "one"]
+
# Get all values as a list with "values()". Once again we need to wrap it in list() to get it out of the iterable.
-list(filled_dict.values()) # => [3, 2, 1]
# Note - Same as above regarding key ordering.
+list(filled_dict.values()) # => [3, 2, 1]
+
# Check for existence of keys in a dictionary with "in"
"one" in filled_dict # => True
@@ -242,6 +258,10 @@ filled_dict.get("four", 4) # => 4
filled_dict.setdefault("five", 5) # filled_dict["five"] is set to 5
filled_dict.setdefault("five", 6) # filled_dict["five"] is still 5
+# Adding to a dictionary
+filled_dict.update({"four":4}) #=> {"one": 1, "two": 2, "three": 3, "four": 4}
+#filled_dict["four"] = 4 #another way to add to dict
+
# Remove keys from a dictionary with del
del filled_dict["one"] # Removes the key "one" from filled dict
@@ -458,6 +478,7 @@ map(add_10, [1, 2, 3]) # => [11, 12, 13]
filter(lambda x: x > 5, [3, 4, 5, 6, 7]) # => [6, 7]
# We can use list comprehensions for nice maps and filters
+# List comprehension stores the output as a list which can itself be a nested list
[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13]
[x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7]