How to check if a string contains an other string (substring) in robot framework?

Question

How to check if a string contains an other string in robot framework?

Something like

${bool} | String Contains | Hello World | World

Get Substring doesn't help, because it needs a start index.

Answer 1

${source}=    Set Variable    this is a string

# ${contains} will be True if "is a" is a part of the ${source} value
${contains}=  Evaluate   "is a" in """${source}"""

# will fail if "is a" is not a part of the ${source} value
Should Be True      "is a" in """${source}"""

# using a robotframework keyword from the String library
# it is actually a wrapper of python's "var_a in var_b" - the previous approaches
Should Contain    ${source}    is a

# as last alternative - an approach that will store 
# the result in a boolean, with RF standard keywords
# ${contains} will be True if "is a" is a part of the ${source} value
${contains}=    Run Keyword And Return Status    Should Contain    ${source}    is a

Hope the example is self-explanatory