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  • no observations error when counting observations with a given value for a string variable

    Hello,
    Stata seems to be exhibiting erratic behavior that I cannot explain. I am just trying to use a particular value of a string variable for an "if" condition, but it keeps returning the error "no observations". I have literally copied the string value out of the codebook output, so I am completely baffled as to why. Trying a count command gives me the same issue. I have no idea what to do next. Hoping someone here has some ideas?

    See code below. I am just trying to look at data points for which catalog=="206.5", but there appears to be no way to do this, as the data tells me that there are no values, even though codebook shows that "206.5" is a valid codebook value for this variable, and even though tabulate shows thousands of data points for this value.

    . codebook catalog

    ---------------------------------------------------------------------------------
    catalog Catalog
    ---------------------------------------------------------------------------------

    Type: String (str8)

    Unique values: 38 Missing "": 0/194,434

    Examples: "56"
    "150"
    "150.5"
    "206.5"

    Warning: Variable has leading blanks.

    . tabulate catalog

    Catalog | Freq. Percent Cum.
    ------------+-----------------------------------
    WK51 | 446 0.23 0.23
    8 | 13,187 6.78 7.01
    12 | 10,984 5.65 12.66
    14 | 902 0.46 13.12
    41 | 1,242 0.64 13.76
    51 | 10,419 5.36 19.12
    56 | 12,729 6.55 25.67
    56.5 | 2,123 1.09 26.76
    100 | 3,243 1.67 28.43
    104 | 11,333 5.83 34.26
    104.5 | 311 0.16 34.42
    109 | 1,089 0.56 34.98
    110 | 907 0.47 35.44
    150 | 38,648 19.88 55.32
    150.5 | 12,775 6.57 61.89
    156 | 61 0.03 61.92
    156.5 | 374 0.19 62.12
    160 | 1,025 0.53 62.64
    161 | 3,931 2.02 64.66
    161.5 | 3,064 1.58 66.24
    200 | 401 0.21 66.45
    206 | 8,912 4.58 71.03
    206.5 | 17,590 9.05 80.08
    209 | 4,917 2.53 82.61
    214 | 1,182 0.61 83.21
    214.5 | 1,411 0.73 83.94
    216 | 932 0.48 84.42
    300 | 75 0.04 84.46
    301 | 18,358 9.44 93.90
    302 | 7,704 3.96 97.86
    303 | 2,056 1.06 98.92
    310 | 49 0.03 98.94
    315 | 983 0.51 99.45
    320 | 70 0.04 99.49
    501 | 983 0.51 99.99
    505 | 8 0.00 99.99
    601 | 9 0.00 100.00
    903 | 1 0.00 100.00
    ------------+-----------------------------------
    Total | 194,434 100.00

    . count if catalog=="206.5"
    0

    . tabulate success term if catalog=="206.5"
    no observations

  • #2
    Nevermind--I found the problem--it was a leading zero. I did not know that Stata would give "206.5" instead of " 206.5" as an output for codebook if there was a leading zero, which is why this did not occur to me before...

    Comment


    • #3
      Note the warning you cite

      Warning: Variable has leading blanks.
      from which it follows that

      Code:
      count if trim(catalog) == "206.5"
      is what to try next.

      EDIT: A leading zero "0" would show as such.
      Last edited by Nick Cox; 30 Jun 2023, 03:14.

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