Formato de cadenas#
Introducción#
The .format() method in Python is used to create strings that include variables, expressions, or values. This method replaces curly brace placeholders {} in a string with values provided inside .format().
x = 1
y = 5
# Display the variables using .format()
brain.print("Position: ({}, {})".format(x, y))
# Display a calculation using .format()
brain.print("Sum: {}".format(5 + 3))
wait(1, SECONDS)
# Display the time using .format()
brain.print("Time: {}".format(timer.time(SECONDS)))
Formatting Numbers with .format – Insert values and expressions into a string.
:.xf– Sets the number of decimal places to show.round– Rounds a number to a given number of decimal places.:,– Adds commas as thousands separators.:.x%– Converts a decimal to a percentage with x decimal places.:#x– Formats a number as hexadecimal.:b– Formats a number as binary.
Combinar cadenas: combina texto y valores.
.format()– Combine strings and variables in a single expression.+ operator– Concatenate strings manually with optional type conversion.
Métodos de cadena: cambiar mayúsculas y minúsculas del texto.
Comprobación de subcadenas: prueba la presencia o la posición del texto.
in– Checks if a word exists in a string.startswith()– Checks if a string begins with a given value.endswith()– Checks if a string ends with a given value.
Secuencias de escape: formatean la salida con caracteres especiales.
Formatting Numbers with .format#
.format can be used to control how numbers appear, including decimal places, rounding, and other formatting styles such as:
Fixed Decimal Places#
.xf controls how many decimal places a number is displayed with.
Usage:
:.xf
Parámetros |
Descripción |
|---|---|
|
La cantidad de decimales a mostrar. |
# Display pi with 2 decimal places
pi = 3.1415926535
brain.print("Pi: {:.2f}".format(pi))
# Output: Pi: 3.14
Rounding Numbers#
round rounds a number to a specific number of decimal places before formatting.
Usage:
round(number, x)
Parámetros |
Descripción |
|---|---|
|
El número a redondear. |
|
La cantidad de decimales a los que redondear. |
# Display a value rounded to only 2 decimal places
value = 5.6789
brain.print("Rounded: {}".format(round(value, 2)))
# Output: Rounded: 5.68
Thousands Separator#
:, inserts commas as thousands separators to make large numbers more readable.
Usage:
:,
Parámetros |
Descripción |
|---|---|
Este especificador de formato no tiene parámetros. |
# Display a large number separated with commas
number = 1234567
brain.print("Formatted: ")
brain.print("{:,}".format(number))
# Output: Formatted: 1,234,567
Percentage#
:.x% formats decimal values as percentages by multiplying the value by 100 and adding a percent sign.
Usage:
:.x%
Parámetros |
Descripción |
|---|---|
|
La cantidad de decimales a mostrar. |
# Display a converted decimal to a percentage
value = 0.875
brain.print("Score: {:.1%}".format(value))
# Output: Score: 87.5%
Hexadecimal#
:#x converts numbers to hexadecimal.
Usage:
:#x
Parámetros |
Descripción |
|---|---|
Este especificador de formato no tiene parámetros. |
# Convert 255 to hexadecimal
number = 255
brain.print("Hex: {:#x}".format(number))
# Output: Hex: 0xff
Binary#
:b converts numbers to binary (base 2).
Usage:
:b
Parámetros |
Descripción |
|---|---|
Este especificador de formato no tiene parámetros. |
# Convert 3 to binary
brain.print("Binary: {:b}".format(3))
# Output: Binary: 11
Combinando cadenas#
Puedes combinar (o concatenar) cadenas utilizando dos métodos:
Using .format#
Insert values directly into the string using {}.
# Display an answer based on the given emotion
emotion = "good"
brain.print("I'm {}, you?".format(emotion))
+ Operator#
Join multiple parts by using +.
Note: Non-strings must first be converted to strings using str().
# Display the x and y values
x = 10
y = 20
brain.print("X: " + str(x) + ", Y: " + str(y))
Métodos de cadena#
Python proporciona métodos integrados para modificar y comprobar cadenas de caracteres.
upper#
upper converts all letters in a string to uppercase.
Usage:
upper()
Parámetros |
Descripción |
|---|---|
Este método no tiene parámetros. |
# Capitalize a string with .upper()
message = "vexcode"
brain.print(message.upper()) # Output: VEXCODE
lower#
lower converts all letters in a string to lowercase.
Usage:
lower()
Parámetros |
Descripción |
|---|---|
Este método no tiene parámetros. |
# Make a string lowercase with .lower()
message = "VEXCODE"
brain.print(message.lower()) # Output: vexcode
Comprobación de subcadenas#
in#
in is a keyword that returns a Boolean indicating whether a substring (word or piece of text) exists in a string.
True– The word exists in the string.False– The word does not exist in the string.
message = "Hey everyone!"
if "Hey" in message:
brain.print("Hello!")
startswith#
startswith returns a Boolean indicating whether a string begins with a given value.
True– The word starts the string.False– The word does not start the string.
Usage:
startswith(substring)
Parámetros |
Descripción |
|---|---|
|
La subcadena que se debe comprobar al principio de la cadena. |
# Check for 'CTE' at the start of a string
message = "CTE Robot"
if message.startswith("CTE"):
brain.print("CTE first!")
endswith#
endswith returns a Boolean indicating whether a string ends with a given value.
True– The word ends the string.False– The word does not end the string.
Usage:
endswith(substring)
Parámetros |
Descripción |
|---|---|
|
La subcadena que se debe comprobar al final de la cadena. |
# Check for `Robot` at the end of a string
message = "CTE Robot"
if message.endswith("Robot"):
brain.print("Robot last!")
Secuencias de escape#
Las secuencias de escape son caracteres especiales que se utilizan dentro de las cadenas de texto para dar formato a la salida de texto.
New Line#
\n moves text to a new line when printing.
# Display text on two lines
brain.print("First line\nSecond line")
Tab Spacing#
\t inserts a tab space between words or numbers.
# Display the quantity of disks
quantity = 2
brain.print("Disks:\t", quantity)