How to get all the individuals in a table with a certain string value

If i have a table with some variables A,B,C... i would like to know how to get all the individuals that have the same string value por a variable. For example, lets say A is Gender; i would like to know how to get all the rows that have 'Male' or 'Female' on the Gender column.

Answer 1

[Star Strider]

See if the findgroups function will produce the desired result.

.

[Alejandro García Candelas]

cant find the way to do it, I have the table from the image and i want to select all the individuals with 'Type'=='1' but matlab doesnt allow to compare with == in cells or datasets

[Star Strider]

Use findgroups on the ‘Type’ variable, then separate the results as desired (here I created two table arrays) —

Type = string(randi([1 2],15,1));
T1 = [table(Type) array2table(rand(15,5))]

T1 = 15×6 table
    Type     Var1        Var2        Var3        Var4        Var5  
    ____    _______    ________    ________    ________    ________

    "1"     0.59136     0.19481    0.023312     0.98485     0.53538
    "1"     0.56687     0.50014     0.69942     0.34835     0.29191
    "1"     0.59777     0.75618     0.55939     0.72626     0.13934
    "2"     0.99397     0.82243     0.21136     0.71282     0.80267
    "2"     0.71459     0.48723     0.19271    0.090322     0.30038
    "1"     0.52004    0.021427     0.73795     0.23881     0.93098
    "1"     0.99037     0.38104     0.10824     0.81794     0.80374
    "1"     0.72778     0.45741    0.026931      0.3331     0.18777
    "2"     0.10657     0.56258     0.69053     0.99675     0.81893
    "1"     0.87947     0.26714     0.88014     0.72234     0.18532
    "2"     0.88679     0.77606     0.75115    0.043026      0.7785
    "1"     0.19891     0.97591     0.84731     0.20003      0.3677
    "2"     0.49285     0.65989     0.78074     0.10065    0.079864
    "2"     0.42923     0.73969     0.99663    0.079554     0.21213
    "2"     0.15099     0.38151     0.57417      0.1541     0.58676

G = findgroups(T1.Type);
Type1 = T1(G==1,:)

Type1 = 8×6 table
    Type     Var1        Var2        Var3       Var4       Var5  
    ____    _______    ________    ________    _______    _______

    "1"     0.59136     0.19481    0.023312    0.98485    0.53538
    "1"     0.56687     0.50014     0.69942    0.34835    0.29191
    "1"     0.59777     0.75618     0.55939    0.72626    0.13934
    "1"     0.52004    0.021427     0.73795    0.23881    0.93098
    "1"     0.99037     0.38104     0.10824    0.81794    0.80374
    "1"     0.72778     0.45741    0.026931     0.3331    0.18777
    "1"     0.87947     0.26714     0.88014    0.72234    0.18532
    "1"     0.19891     0.97591     0.84731    0.20003     0.3677

Type2 = T1(G==2,:)

Type2 = 7×6 table
    Type     Var1       Var2       Var3        Var4        Var5  
    ____    _______    _______    _______    ________    ________

    "2"     0.99397    0.82243    0.21136     0.71282     0.80267
    "2"     0.71459    0.48723    0.19271    0.090322     0.30038
    "2"     0.10657    0.56258    0.69053     0.99675     0.81893
    "2"     0.88679    0.77606    0.75115    0.043026      0.7785
    "2"     0.49285    0.65989    0.78074     0.10065    0.079864
    "2"     0.42923    0.73969    0.99663    0.079554     0.21213
    "2"     0.15099    0.38151    0.57417      0.1541     0.58676

It is easier here to create the string array for ‘Type’. The code will work the same way for character variables.

.

[Alejandro García Candelas]

Oh well that was a bit not intuitive but MATLAB is what it is. Really helpful thanks a lot

[Star Strider]

My pleasure!

Another option would be the unique function, however findgroups is a bit more robust.

If my Answer helped you solve your problem, please Accept it!

.

[Steven Lord]

You could also use string or categorical operations.

load patients
T = table(LastName, Gender, Smoker);
T.Gender = categorical(T.Gender); % Change from cellstr to categorical
head(T)

ans = 8×3 table
      LastName      Gender    Smoker
    ____________    ______    ______

    {'Smith'   }    Male      true  
    {'Johnson' }    Male      false 
    {'Williams'}    Female    false 
    {'Jones'   }    Female    false 
    {'Brown'   }    Female    false 
    {'Davis'   }    Female    false 
    {'Miller'  }    Female    true  
    {'Wilson'  }    Male      false 

allMales = T(T.Gender == 'Male', :) % 'Male' converted to categorical for comparison

allMales = 47×3 table
      LastName       Gender    Smoker
    _____________    ______    ______

    {'Smith'    }     Male     true  
    {'Johnson'  }     Male     false 
    {'Wilson'   }     Male     false 
    {'Moore'    }     Male     false 
    {'Jackson'  }     Male     false 
    {'White'    }     Male     true  
    {'Martin'   }     Male     true  
    {'Thompson' }     Male     true  
    {'Martinez' }     Male     false 
    {'Robinson' }     Male     false 
    {'Hall'     }     Male     false 
    {'Hernandez'}     Male     false 
    {'King'     }     Male     true  
    {'Scott'    }     Male     false 
    {'Green'    }     Male     false 
    {'Baker'    }     Male     true  

allSmiths = T(T.LastName == "Smith", :) % "Smith" is a string

allSmiths = 1×3 table
    LastName     Gender    Smoker
    _________    ______    ______

    {'Smith'}     Male     true  

allStartsWithW = T(startsWith(T.LastName, "W"), :) % Can perform other string ops

allStartsWithW = 9×3 table
       LastName       Gender    Smoker
    ______________    ______    ______

    {'Williams'  }    Female    false 
    {'Wilson'    }    Male      false 
    {'White'     }    Male      true  
    {'Walker'    }    Female    true  
    {'Wright'    }    Female    true  
    {'Ward'      }    Male      false 
    {'Watson'    }    Female    true  
    {'Wood'      }    Male      false 
    {'Washington'}    Female    false