Skip to content

3.4.3.4 Text

Text-handling directives provide a comprehensive set of tools for string manipulation, including checking text properties, manipulating string content, converting data types, and formatting text output, to meet the various text-processing needs of everyday programming.

Property Detection

Blocks Note
image Text input field: Converts the variable in the input field to a string type.
image Determine whether the text consists of numbers or letters.
image Check if the text is empty.
image Determine the length of the text.

String Operations

Blocks Note
image Concatenate strings or numbers and return a string. For example, concatenating "world" and "hello" returns the string "worldhello".
image Conditional check: Determine whether a string contains a specific character. If it does, the result is true (1); if not, the result is false (0). For example, since "apple" contains the letter "a," the result is true.
image Retrieve a single character from a string, starting from 1.
image Retrieve a contiguous segment of characters from the string.
image Find a character, or find the first or last occurrence of a character or number in a string.

Type conversion

Blocks Note
image Convert a string to an integer or a decimal number.
image Convert the number to an ASCII character.
image Convert characters to ASCII values.
image Convert the number to a string.

Formatted output

Blocks Note
image Formatted strings—% placeholder notation. For example: If there is a variable num=3.14159, using “Value: %.2f ”%num will produce the result “Value: 3.14”. %.2f means: Format the variable as a floating-point number and retain two decimal places.
image Formatted strings—format placeholder notation. For example, the format “Value: {:.3}” (5) will produce the result “Value: 5”.Detailed explanation: In “Value: {:.3}” format(5), since an integer is passed in, it is treated as a string. The precision .3 indicates that the first 3 characters should be truncated, but “5” consists of only 1 character, so the output is “Value: 5”.
image Text escape characters are a type of special character. \n represents a newline character, which moves the cursor to the beginning of the next line. \r represents a carriage return character, which positions the cursor at the beginning of the current line without moving to the next line. \n\r first moves the cursor to the next line and then positions it at the beginning of the current line. \r\n moves the cursor to the beginning of the current line and then creates a new line at that position. \b represents the backspace character, similar to the Backspace key on a keyboard. \t represents a tab character, moving the cursor to the next tab position, similar to using the Tab key in a document. denotes the backslash character; to use a backslash ( ‘\’), you must use two backslashes.