ABAP. Instruciones de control

IF

La comparación de variables constantes y literales es:


Comparaciones comunes y formas alternativas

Comparison	Alternate Forms	True When
v1 = v2	EQ	v1 equals v2
v1 <> v2	NE, ><	v1 does not equal v2
v1 > v2	GT	v1 is greater than v2
v1 < v2	LT	v1 is less than v2
v1 >= v2	GE, =>	v1 is greater than or equal to v2
v1 <= v2	LE, =<	v1 is less than or equal to v2
v1 between v2 and v3		v1 lies between v2 and v3 (inclusive)
not v1 between v2 and v3		v1 lies outside of the range v2 to v3 (inclusive)

Durante las comparaciones entre variables, puede haber conversiones.
Para eso se usa el ANALISIS DE PROGRAMA.
Conversion de Literales

Description	Data Type
Numbers one to nine digits long	i
Numbers 10 or more digits long	p
All others	c

Conversiones de variables en la comparación.

• If one field is type f, the other is converted to type f.
• If one field is type p, the other is converted to type p.
• If one field is type i, the other is converted to type i.
• If one field is type d, the other is converted to type d. Types c and n, however, are not converted. They are compared directly.
• If one field is type t, the other is converted to type t. Types c and n, however, are not converted. They are compared directly.
• If one field is type n, both are converted to type p (at this point, the other field can only be type c or x).
• At this point, one field will be type c and the other will be type x. x is converted to type c.

Conversions follow the same rules as those performed by the move statement. Type conversions are fully detailed in the ABAP/4 keyword documentation under the heading "Relational Operators for All Data Types."

COMPARACIÓN DE STRINGS DE CARACTERES
Table 10.3 Special Operators for Character Strings

Operator	Means	True When	Case Sensitive?	Trailing Blanks Ignored?
v1 CO v2	Contains Only	v1 is composed solely of characters in v2	Yes	No
v1 CN v2	not v1 CO v2	v1 contains characters that are not in v2	Yes	No
v1 CA v2	Contains Any	v1 contains at least one character in v2	Yes	No
v1 NA v2	not v1 CA v2	v1 does not contain any character in v2	Yes	No
v1 CS v2	Contains String	v1 contains the character string v2	No	Yes
v1 NS v2	not v1 CS v2	v1 does not contain the character string v2	No	Yes
v1 CP v2	Contains Pattern	v1 contains the pattern in v2	No	Yes
v1 NP v2	not v1 CP v2	v1 does not contain the pattern in v2	No	Yes

These operators can be used in any comparison expression. The CS, NS, CP, and NP operators ignore trailing blanks and are not case sensitive.

Esto es válido para variables, literales y strings.

Contains Pattern: Se pueden usar las siguientes pattern:

Table 10.4 CP and NP Operators

Character	Used to
*	Match any sequence of characters.
+	Match any single character.
#	Interpret the next character literally.

sy-fdpos. Es una variable del sistema que se puede usar para comparaciones.

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Sentencia Case.

La sintaxis de la sentencia case es la siguiente:

case v1.
  when v2 [ or vn ... ].
      ---
    when v3 [ or vn ... ].
      ---
    [ when others.
      --- ]
  endcase.

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