Positional formatting
Regular Expressions in Python
Maria Eugenia Inzaugarat
Data scientist
What is string formatting?
String interpolation
Insert a custom string or variable in predefined text:
custom_string = "String formatting"
print(f"{custom_string} is a powerful technique")
String formatting is a powerful technique
- Usage:
- Title in a graph
- Show message or error
- Pass a statement to a function
Methods for formatting
- Positional formatting
- Formatted string literals
- Template method
Positional formatting
- Placeholder replace by value
str.format()
print("Machine learning provides {} the ability to learn {}".format("systems", "automatically"))
Machine learning provides systems the ability to learn automatically
Positional formatting
- Use variables for both the initial string and the values passed into the method
my_string = "{} rely on {} datasets"
method = "Supervised algorithms"
condition = "labeled"
print(my_string.format(method, condition))
Supervised algorithms rely on labeled datasets
Reordering values
- Include an index number into the placeholders to reorder values
print("{} has a friend called {} and a sister called {}".format("Betty", "Linda", "Daisy"))
Betty has a friend called Linda and a sister called Daisy
print("{2} has a friend called {0} and a sister called {1}".format("Betty", "Linda", "Daisy"))
Daisy has a friend called Betty and a sister called Linda
Named placeholders
- Specify a name for the placeholders
tool="Unsupervised algorithms"
goal="patterns"
print("{title} try to find {aim} in the dataset".format(title=tool, aim=goal))
Unsupervised algorithms try to find patterns in the dataset
Named placeholders
my_methods = {"tool": "Unsupervised algorithms", "goal": "patterns"}
print('{data[tool]} try to find {data[goal]} in the dataset'.format(data=my_methods))
Unsupervised algorithms try to find patterns in the dataset
Format specifier
- Specify data type to be used:
{index:specifier}
print("Only {0:f}% of the {1} produced worldwide is {2}!".format(0.5155675, "data", "analyzed"))
Only 0.515568% of the data produced worldwide is analyzed!
print("Only {0:.2f}% of the {1} produced worldwide is {2}!".format(0.5155675, "data", "analyzed"))
Only 0.52% of the data produced worldwide is analyzed!
Formatting datetime
from datetime import datetime
print(datetime.now())
datetime.datetime(2019, 4, 11, 20, 19, 22, 58582)
print("Today's date is {:%Y-%m-%d %H:%M}".format(datetime.now()))
Today's date is 2019-04-11 20:20
Let's practice!
Regular Expressions in Python
